<?xmlversion='1.0' encoding='utf-8'?>version="1.0" encoding="UTF-8"?> <!DOCTYPE rfc [ <!ENTITY nbsp " "> <!ENTITY zwsp "​"> <!ENTITY nbhy "‑"> <!ENTITY wj "⁠"> ]><?xml-stylesheet type="text/xsl" href="rfc2629.xslt" ?> <!-- generated by https://github.com/cabo/kramdown-rfc version 1.6.15 (Ruby 3.1.2) --><rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902" docName="draft-ietf-add-ddr-10" number="9462" submissionType="IETF" category="std" consensus="true" tocInclude="true" sortRefs="true" symRefs="true" updates="" obsoletes="" xml:lang="en" version="3"> <!-- xml2rfc v2v3 conversion 3.13.1 --> <front> <title abbrev="DDR">Discovery of Designated Resolvers</title> <seriesInfoname="Internet-Draft" value="draft-ietf-add-ddr-10"/>name="RFC" value="9462"/> <author initials="T." surname="Pauly" fullname="Tommy Pauly"> <organization>Apple Inc.</organization> <address> <postal> <street>One Apple Park Way</street><city>Cupertino, California 95014</city><city>Cupertino</city> <region>California</region> <code>95014</code> <country>United States of America</country> </postal> <email>tpauly@apple.com</email> </address> </author> <author initials="E." surname="Kinnear" fullname="Eric Kinnear"> <organization>Apple Inc.</organization> <address> <postal> <street>One Apple Park Way</street><city>Cupertino, California 95014</city><city>Cupertino</city> <region>California</region> <code>95014</code> <country>United States of America</country> </postal> <email>ekinnear@apple.com</email> </address> </author> <author initials="C. A." surname="Wood" fullname="Christopher A. Wood"> <organization>Cloudflare</organization> <address> <postal> <street>101 Townsend St</street> <city>San Francisco</city> <region>California</region> <code>94107</code> <country>United States of America</country> </postal> <email>caw@heapingbits.net</email> </address> </author> <author initials="P." surname="McManus" fullname="Patrick McManus"> <organization>Fastly</organization> <address> <email>mcmanus@ducksong.com</email> </address> </author> <author initials="T." surname="Jensen" fullname="Tommy Jensen"> <organization>Microsoft</organization> <address> <email>tojens@microsoft.com</email> </address> </author> <dateyear="2022" month="August" day="05"/> <area>Internet</area> <workgroup>ADD</workgroup>year="2023" month="September"/> <area>int</area> <workgroup>add</workgroup> <!-- [rfced] Please insert any keywords (beyond those that appear in the title) for use on <https://www.rfc-editor.org/search>. --> <!-- [rfced] Datatracker "idnits" output for the original approved document included the following warning. Please let us know if any changes are needed as related to this warning: == There are 10 instances of lines with non-RFC2606-compliant FQDNs in the document. --> <abstract> <t>This document defines Discovery of Designated Resolvers (DDR), a mechanism for DNS clients to use DNS records to discover a resolver's encrypted DNS configuration. An encrypted DNS resolver discovered in this manner is referred to as a "Designated Resolver". This mechanism can be used to move from unencrypted DNS to encrypted DNS when only the IP address of a resolver is known. This mechanism is designed to be limited to cases where unencrypted DNS resolvers and their designated resolvers are operated by the same entity or cooperating entities. It can also be used to discover support for encrypted DNS protocols when the name of an encrypted DNS resolver isknown.</t> </abstract> <note removeInRFC="true"> <name>Discussion Venues</name> <t>Discussion ofknown. <!-- [rfced] Abstract and Section 2: We see both the singular form "mechanism" and the plural form "mechanisms" in this documenttakes place on the Adaptive DNSwhen specifically discussing DDR. Which is correct - singular or plural? Original: This document defines DiscoveryWorking Group mailing list (add@ietf.org), which is archived at <eref target="https://mailarchive.ietf.org/arch/browse/add/"/>.</t> <t>Sourceof Designated Resolvers (DDR), a mechanism for DNS clients to use DNS records to discover a resolver's encrypted DNS configuration. An encrypted DNS resolver discovered in thisdraft and an issue trackermanner is referred to as a "Designated Resolver". This mechanism can befound at <eref target="https://github.com/ietf-wg-add/draft-ietf-add-ddr"/>.</t> </note>used to move from unencrypted DNS to encrypted DNS when only the IP address of a resolver is known. This mechanism is designed to be limited to cases where unencrypted DNS resolvers and their designated resolvers are operated by the same entity or cooperating entities. ... DDR: Discovery of Designated Resolvers. Refers to the mechanisms defined in this document. --> </t> </abstract> </front> <middle> <section anchor="introduction"> <name>Introduction</name> <t>When DNS clients wish to use encrypted DNS protocols such asDNS-over-TLSDNS over TLS (DoT) <xref target="RFC7858"/>,DNS-over-QUICDNS over QUIC (DoQ) <xref target="RFC9250"/>, orDNS-over-HTTPSDNS over HTTPS (DoH) <xref target="RFC8484"/>, they can require additional information beyond the IP address of the DNS server, such as the resolver's hostname, alternate IP addresses, non-standard ports, or URItemplates.Templates. However, common configuration mechanisms only provide the resolver's IP address during configuration. Such mechanisms include network provisioning protocols like DHCP <xref target="RFC2132"/> <xref target="RFC8415"/> and IPv6 Router Advertisement (RA) options <xref target="RFC8106"/>, as well as manualconfiguration.</t>configuration. <!-- [rfced] Sections 1 and 6.5: We see different RFCs cited for IPv6 Router Advertisement options: RFC 8106 in Section 1 but RFC 4861 in Section 6.5. Should the same RFC be cited in both sections as related to IPv6 Router Advertisement options? Please note, however, that we do not see any mention of Router Advertisement options in RFC 4861 - only Neighbor Discovery options. Should the sentence in Section 6.5 be updated to avoid possible confusion? Original: Such mechanisms include network provisioning protocols like DHCP [RFC2132] [RFC8415] and IPv6 Router Advertisement (RA) options [RFC8106], as well as manual configuration. ... Discovery of network-designated resolvers (DNR, [I-D.ietf-add-dnr]) allows a network to provide designation of resolvers directly through DHCP [RFC2132] [RFC8415] and IPv6 Router Advertisement (RA) [RFC4861] options. --> </t> <t>This document defines two mechanisms for clients to discover designated resolvers that support these encrypted protocols using DNS server Service Binding(SVCB,(SVCB) records <xreftarget="I-D.ietf-dnsop-svcb-https"/>) records:</t>target="RFC9460"/>:</t> <ol spacing="normal" type="1"><li>When only an IP address of an Unencrypted DNS Resolver is known, the client queries aspecial use domain nameSpecial-Use Domain Name (SUDN) <xref target="RFC6761"/> to discover DNS SVCB records associated with one or more Encrypted DNS Resolvers the Unencrypted DNS Resolver has designated for use when support for DNS encryption is requested (<xref target="bootstrapping"/>).</li> <li>When the hostname of an Encrypted DNS Resolver is known, the client requests details by sending a query for a DNS SVCB record. This can be used to discover alternate encrypted DNS protocols supported by a known server, or to provide details if a resolver name is provisioned by a network (<xref target="encrypted"/>).</li> </ol> <t>Both of these approaches allow clients to confirm that a discovered Encrypted DNS Resolver is designated by the originally provisioned resolver. "Designated" in this context means that the resolvers are operated by the same entity or cooperating entities; for example, the resolvers are accessible on the same IP address, or there is a certificate that contains the IP address for the original designating resolver.</t> <section anchor="specification-of-requirements"> <name>Specification of Requirements</name> <t>The key words"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY","<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and"OPTIONAL""<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as described inBCP 14BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they appear in all capitals, as shown here.</t> </section> </section> <section anchor="terminology"> <name>Terminology</name> <t>This document defines the following terms:</t> <dl> <dt>DDR:</dt> <dd> <t>Discovery of Designated Resolvers.Refers"DDR" refers to the mechanisms defined in this document.</t> </dd> <dt>Designated Resolver:</dt> <dd> <t>A resolver, presumably an Encrypted DNS Resolver, designated by another resolver for use in its own place. This designation can be verified with TLS certificates.</t> </dd> <dt>Encrypted DNS Resolver:</dt> <dd> <t>A DNS resolver using any encrypted DNS transport. This includes current mechanisms such as DoH, DoT, and DoQ, as well as future mechanisms.</t> </dd> <dt>Unencrypted DNS Resolver:</dt> <dd> <t>A DNS resolver using a transport without encryption, historically TCP or UDP port 53.</t> </dd> </dl> </section> <section anchor="dns-service-binding-records"> <name>DNS Service Binding Records</name> <t>DNS resolvers can advertise one or more Designated Resolvers that may offer support over encrypted channels and are controlled by the same entity.</t> <t>When a client discovers Designated Resolvers, it learns information such as the supported protocols and ports. This information is provided in ServiceModeService Binding (SVCB)SVCB records for DNSServers,servers, although AliasMode SVCB records can be used to direct clients to the needed ServiceMode SVCB record per <xreftarget="I-D.ietf-dnsop-svcb-https"/>.target="RFC9460"/>. The formatting of these records, including the DNS-unique parameters such as "dohpath", are defined by <xreftarget="I-D.ietf-add-svcb-dns"/>.</t>target="RFC9461"/>.</t> <t>The following is an example of an SVCB record describing a DoH server discovered by querying for <tt>_dns.example.net</tt>:</t> <!-- [rfced] Please review each artwork element. Specifically, should any artwork element be tagged as sourcecode or another element? Please see <https://www.rfc-editor.org/materials/sourcecode-types.txt>; if the current list of preferred values for "type" does not contain an applicable type, please let us know. Also, if you choose to use the sourcecode tag, it is acceptable to leave the "type" attribute not set. --> <artwork><![CDATA[ _dns.example.net. 7200 IN SVCB 1 example.net. ( alpn=h2 dohpath=/dns-query{?dns} ) ]]></artwork> <t>The following is an example of an SVCB record describing a DoT server discovered by querying for <tt>_dns.example.net</tt>:</t> <artwork><![CDATA[ _dns.example.net. 7200 IN SVCB 1 dot.example.net ( alpn=dot port=8530 ) ]]></artwork> <t>The following is an example of an SVCB record describing a DoQ server discovered by querying for <tt>_dns.example.net</tt>:</t> <artwork><![CDATA[ _dns.example.net. 7200 IN SVCB 1 doq.example.net ( alpn=doq port=8530 ) ]]></artwork> <t>If multiple Designated Resolvers are available, using one or more encrypted DNS protocols, the resolver deployment can indicate a preference using the priority fields in each SVCB record <xreftarget="I-D.ietf-dnsop-svcb-https"/>.</t>target="RFC9460"/>.</t> <t>If the client encounters a mandatory parameter in an SVCB record it does not understand, itMUST NOT<bcp14>MUST NOT</bcp14> use that record to discover a Designated Resolver, in accordance with <xref section="8" sectionFormat="of"target="I-D.ietf-dnsop-svcb-https"/>.target="RFC9460"/>. The client can still use other records in the same response if the client can understand all of their mandatory parameters. This allows future encrypted deployments to simultaneously support protocols even if a given client is not aware of all those protocols. For example, if the Unencrypted DNS Resolver returns three SVCBrecords,records -- one for DoH, one for DoT, and one for a yet-to-existprotocol,protocol -- a clientwhichthat only supports DoH and DoT should be able to use those records while safely ignoring the third record.</t> <t>To avoid name lookup deadlock, clients that use Designated Resolvers need to ensure that a specific Encrypted Resolver is not used for any queries that are needed to resolve the name of the resolver itself or to perform certificate revocation checks for the resolver, as described in <xref section="10" sectionFormat="of" target="RFC8484"/>. Designated Resolvers need to ensure that this deadlock isavoidableavoidable, as also described in <xref section="10" sectionFormat="of"target="RFC8484"/>.</t>target="RFC8484"/>. <!-- [rfced] Sections 3, 4.1, and 4.2: Should these instances of "Encrypted Resolver" be "Encrypted DNS Resolver" per the rest of this document, or "encrypted resolver" per companion documents 9463 (draft-ietf-add-dnr) and 9464 (draft-ietf-ipsecme-add-ike), assuming that the term is used more generally in the other documents? Original: To avoid name lookup deadlock, clients that use Designated Resolvers need to ensure that a specific Encrypted Resolver is not used for any queries that are needed to resolve the name of the resolver itself or to perform certificate revocation checks for the resolver, as described in Section 10 of [RFC8484]. ... Use without validation can allow an attacker to direct traffic to an Encrypted Resolver that is unrelated to the original Unencrypted DNS Resolver, as described in Section 7. ... If the IP address is not shared, opportunistic use allows for attackers to redirect queries to an unrelated Encrypted Resolver, as described in Section 7. --> </t> <t>This document focuses on discovering DoH, DoT, and DoQ Designated Resolvers. Other protocols can also use the format defined by <xreftarget="I-D.ietf-add-svcb-dns"/>.target="RFC9461"/>. However, if any such protocol does not involve some form of certificate validation, new validation mechanisms will need to be defined to support validating designation as defined in <xref target="verified"/>.</t> </section> <section anchor="bootstrapping"> <name>Discovery Using Resolver IP Addresses</name> <t>When a DNS client is configured with an Unencrypted DNS Resolver IP address, itSHOULD<bcp14>SHOULD</bcp14> query the resolver for SVCB records of a service with a scheme of "dns" and an Authority of "resolver.arpa" before making other queries. This allows the client to switch to using Encrypted DNS for all other queries, if possible. Specifically, the client issues a query for <tt>_dns.resolver.arpa.</tt> with the SVCB resource record type (64) <xreftarget="I-D.ietf-dnsop-svcb-https"/>.</t>target="RFC9460"/>. <!-- [rfced] Section 4: This text has the only instance of initial-capitalized "Authority" in this document or this cluster of documents (https://www.rfc-editor.org/cluster_info.php?cid=C461). Is the capitalization necessary? Original: When a DNS client is configured with an Unencrypted DNS Resolver IP address, it SHOULD query the resolver for SVCB records of a service with a scheme of "dns" and an Authority of "resolver.arpa" before making other queries. --> </t> <t>Responses to the SVCB query for the "resolver.arpa" SUDN describe Designated Resolvers. To ensure that different Designated Resolver configurations can be correctly distinguished and associated with A and AAAA records for the resolver, ServiceMode SVCB responses to these queriesMUST NOT<bcp14>MUST NOT</bcp14> use the "." or "resolver.arpa" value for the TargetName. Similarly, clientsMUST NOT<bcp14>MUST NOT</bcp14> perform A or AAAA queries for "resolver.arpa".</t> <t>The following is an example of an SVCB record describing a DoH server discovered by querying for <tt>_dns.resolver.arpa</tt>:</t> <artwork><![CDATA[ _dns.resolver.arpa. 7200 IN SVCB 1 doh.example.net ( alpn=h2 dohpath=/dns-query{?dns} ) ]]></artwork> <t>The following is an example of an SVCB record describing a DoT server discovered by querying for <tt>_dns.resolver.arpa</tt>:</t> <artwork><![CDATA[ _dns.resolver.arpa. 7200 IN SVCB 1 dot.example.net ( alpn=dot port=8530 ) ]]></artwork> <t>The following is an example of an SVCB record describing a DoQ server discovered by querying for <tt>_dns.resolver.arpa</tt>:</t> <artwork><![CDATA[ _dns.resolver.arpa. 7200 IN SVCB 1 doq.example.net ( alpn=doq port=8530 ) ]]></artwork> <t>If the recursive resolver that receives this query has one or more Designated Resolvers, it will return the corresponding SVCB records. When responding to these special queries for "resolver.arpa", the recursive resolverSHOULD<bcp14>SHOULD</bcp14> include the A and AAAA records for the name of the Designated Resolver in the Additional Answers section. This will save the DNS client an additional round trip to retrieve the address of the designated resolver; see <xref section="5" sectionFormat="of"target="I-D.ietf-dnsop-svcb-https"/>.</t>target="RFC9460"/>.</t> <t>Designated ResolversSHOULD<bcp14>SHOULD</bcp14> be accessible using the IP address families that are supported by their associated Unencrypted DNS Resolvers. If an Unencrypted DNS Resolver is accessible using an IPv4 address, it ought to provide an A record for an IPv4 address of the Designated Resolver; similarly, if it is accessible using an IPv6 address, it ought to provide a AAAA record for an IPv6 address of the Designated Resolver. The Designated ResolverMAY<bcp14>MAY</bcp14> support more address families than the Unencrypted DNS Resolver, but itSHOULD NOT<bcp14>SHOULD NOT</bcp14> support fewer. If this is not done, clients that only have connectivity over one address family might not be able to access the Designated Resolver.</t> <t>If the recursive resolver that receives this query has no Designated Resolvers, itSHOULD<bcp14>SHOULD</bcp14> return NODATA for queries to the "resolver.arpa" zone, to provide a consistent and accurate signal to clients that it does not have a Designated Resolver.</t> <section anchor="use-of-designated-resolvers"> <name>Use of Designated Resolvers</name> <t>When a client discovers Designated Resolvers from an Unencrypted DNS Resolver IP address, it can choose to use these Designated Resolvers eitherautomatically,(1) automatically orbased(2) based on some other policy, heuristic, or user choice.</t> <t>This document defines two preferred methodstofor automaticallyuseusing Designated Resolvers:</t> <ul spacing="normal"> <li>Verified Discovery (<xref target="verified"/>), for when a TLS certificate can be used to validate the resolver's identity.</li> <li>Opportunistic Discovery (<xref target="opportunistic"/>), for when a resolver's IP address is a private or local address.</li> </ul> <t>A clientMAY<bcp14>MAY</bcp14> additionally use a discovered Designated Resolver without either of these methods, based on implementation-specific policy or user input. Details of such policy are out of scopeoffor this document. ClientsMUST NOT<bcp14>MUST NOT</bcp14> automatically use a Designated Resolver without some sort of validation, such as the two methods defined in this document or a future mechanism. Use without validation can allow an attacker to direct traffic to an Encrypted Resolver that is unrelated to the original Unencrypted DNS Resolver, as described in <xref target="security"/>.</t> <t>A clientMUST NOT re-use<bcp14>MUST NOT</bcp14> reuse a designation discovered using the IP address of one Unencrypted DNS Resolver in place of any other Unencrypted DNS Resolver. Instead, the client needs to repeat the discovery process to discover the Designated Resolver of the other Unencrypted DNS Resolver. In other words, designations are per-resolver andMUST NOT<bcp14>MUST NOT</bcp14> be used to configure the client's universal DNS behavior. This ensures in all cases that queries are being sent to a party designated by the resolver originally being used.</t> <section anchor="use-of-designated-resolvers-across-network-changes"> <name>Use of Designated Resolvers acrossnetwork changes</name>Network Changes</name> <t>If a client is configured with the same Unencrypted DNS Resolver IP address on multiple different networks, a Designated Resolver that has been discovered on one networkSHOULD NOT<bcp14>SHOULD NOT</bcp14> be reused on any of the other networks without repeating the discovery process for each network, since the same IP address may be used for different servers on the different networks.</t> </section> </section> <section anchor="verified"> <name>Verified Discovery</name> <t>Verified Discovery is a mechanism that allows the automatic use of a Designated Resolver that supports DNS encryption that performs a TLS handshake.</t> <t>In order to be considered a verified Designated Resolver, the TLS certificate presented by the Designated Resolver needs to pass the following checks made by the client:</t> <ol spacing="normal" type="1"><li>The clientMUST<bcp14>MUST</bcp14> verify the chain of certificates up to a trust anchor as described in <xref section="6" sectionFormat="of" target="RFC5280"/>. This <bcp14>SHOULD</bcp14> use the default system or application trust anchors, unless otherwise configured. <!-- [rfced] Section 4.2: To what does "This" refer in this sentence - the client, verifying the chain of certificates, or something else? If the suggested text is not correct, please provide clarifying text. Original (the previous sentence is included for context): 1. The client MUST verify the chain of certificates up to a trust anchor as described in Section 6 of [RFC5280]. This SHOULD use the default system or application trust anchors, unless otherwiseconfigured.</li> <li>Theconfigured. Suggested: 1. The client MUST verify the chain of certificates up to a trust anchor as described in Section 6 of [RFC5280]; the client therefore SHOULD use the default system or application trust anchors, unless otherwise configured. --> </li> <li>The client <bcp14>MUST</bcp14> verify that the certificate contains the IP address of the designating Unencrypted DNS Resolver in an iPAddress entry of the subjectAltName extension as described in <xref section="4.2.1.6" sectionFormat="of" target="RFC5280"/>.</li> </ol> <t>If these checks pass, the clientSHOULD<bcp14>SHOULD</bcp14> use the discovered Designated Resolver for any cases in which it would have otherwise used the Unencrypted DNS Resolver, so as to prefer Encrypted DNS whenever possible.</t> <t>If these checks fail, the clientMUST NOT<bcp14>MUST NOT</bcp14> automatically use the discovered Designated Resolver if this designation was only discovered via a <tt>_dns.resolver.arpa.</tt> query (if the designation was advertised directly by the network as described in <xref target="dnr-interaction"/>, the server can still be used). Additionally, the clientSHOULD<bcp14>SHOULD</bcp14> suppress any further queries for Designated Resolvers using this Unencrypted DNS Resolver for the length of time indicated by the SVCB record's Time to Live (TTL) in order to avoid excessive queries that will lead to further failed validations. The clientMAY<bcp14>MAY</bcp14> issue new queries if the SVCB record's TTL is excessively long (as determined by client policy) to minimize the length of time an intermittent attacker can prevent the use of encrypted DNS.</t> <t>If the Designated Resolver and the Unencrypted DNS Resolver share an IP address, clientsMAY<bcp14>MAY</bcp14> choose to opportunistically use the Designated Resolver even without this certificate check (<xref target="opportunistic"/>). If the IP address is not shared, opportunistic use allows for attackers to redirect queries to an unrelated Encrypted Resolver, as described in <xref target="security"/>.</t> <t>Connections to a Designated Resolver can use a different IP address than the IP address of the Unencrypted DNSResolver, such asResolver -- for example, if the process of resolving the SVCB service yields additional addresses. Even when a different IP address is used for the connection, the TLS certificate checks described in this section still apply for the original IP address of the Unencrypted DNS Resolver.</t> </section> <section anchor="opportunistic"> <name>Opportunistic Discovery</name> <t>There are situations where Verified Discovery of encrypted DNS configuration over unencrypted DNS is not possible. This includes Unencrypted DNS Resolvers on private IP addresses <xref target="RFC1918"/>, Unique Local Addresses (ULAs) <xref target="RFC4193"/>, andLink Local AddressesLink-Local addresses <xref target="RFC3927"/> <xref target="RFC4291"/>, whose identity cannot be safely confirmed using TLS certificates under mostconditions.</t>conditions. <!-- [rfced] Section 4.3: We had trouble following this sentence. To what does "This includes" refer? If the suggested text is not correct, please provide clarifying text. Original (the previous sentence is included for context): There are situations where Verified Discovery of encrypted DNS configuration over unencrypted DNS is not possible. This includes Unencrypted DNS Resolvers on private IP addresses [RFC1918], Unique Local Addresses (ULAs) [RFC4193], and Link Local Addresses [RFC3927] [RFC4291], whose identity cannot be safely confirmed using TLS certificates under most conditions. Suggested: There are situations where Verified Discovery of encrypted DNS configuration over unencrypted DNS is not possible. For example, the identities of Unencrypted DNS Resolvers on private IP addresses [RFC1918], Unique Local Addresses (ULAs) [RFC4193], and Link-Local addresses [RFC3927] [RFC4291] cannot be safely confirmed using TLS certificates under most conditions. --> </t> <t>AnOpportunistic Privacy Profileopportunistic privacy profile is defined for DoT in <xref section="4.1" sectionFormat="of" target="RFC7858"/> as a mode in which clients do not validate the name of the resolver presented in the certificate. ThisOpportunistic Privacy Profileopportunistic privacy profile similarly applies to DoQ <xref target="RFC9250"/>. For this profile, <xref section="4.1" sectionFormat="of" target="RFC7858"/> explains that clients might or might not validate the resolver; however, even if clients choose to perform some certificate validation checks, they will not be able to validate the names presented in the SubjectAlternativeName field of the certificate for private and local IP addresses.</t> <t>A clientMAY<bcp14>MAY</bcp14> use information from the SVCB record for "_dns.resolver.arpa" with thisOpportunistic Privacy Profileopportunistic privacy profile as long as the IP address of the Encrypted DNS Resolver does not differ from the IP address of the Unencrypted DNS Resolver. ClientsSHOULD<bcp14>SHOULD</bcp14> use this mode only for resolvers using private or local IP addresses, since resolvers that use other addresses are able to provision TLS certificates for their addresses.</t> </section> </section> <section anchor="encrypted"> <name>Discovery Using Resolver Names</name> <t>A DNS client that already knows the name of an Encrypted DNS Resolver can use DDR to discover details about all supported encrypted DNS protocols. This situation can arise if a client has been configured to use a given Encrypted DNS Resolver, or if a network provisioning protocol (such as DHCP or IPv6Router Advertisements)RAs) provides a name for an Encrypted DNS Resolver alongside the resolver IP address, such as by using Discovery ofNetworkNetwork-designated Resolvers (DNR) <xreftarget="I-D.ietf-add-dnr"/>.</t>target="RFC9463"/>.</t> <t>For these cases, the client simply sends a DNS SVCB query using the known name of the resolver. This query can be issued to the named Encrypted DNS Resolver itself or to any other resolver. Unlike the case of bootstrapping from an Unencrypted DNS Resolver (<xref target="bootstrapping"/>), these recordsSHOULD<bcp14>SHOULD</bcp14> be available in the public DNS if the same domain name's A or AAAA records are available in the public DNS to allow using any resolver to discover another resolver's Designated Resolvers. When the name can only be resolved in private namespaces, these recordsSHOULD<bcp14>SHOULD</bcp14> be available to the same audience as the A and AAAA records.</t> <t>For example, if the client already knows about a DoT server <tt>resolver.example.com</tt>, it can issue an SVCB query for <tt>_dns.resolver.example.com</tt> to discover if there are other encrypted DNS protocols available. In the following example, the SVCB answers indicate that <tt>resolver.example.com</tt> supports both DoH andDoT,DoT and that the DoH server indicates a higher priority than the DoT server.</t> <artwork><![CDATA[ _dns.resolver.example.com. 7200 IN SVCB 1 resolver.example.com. ( alpn=h2 dohpath=/dns-query{?dns} ) _dns.resolver.example.com. 7200 IN SVCB 2 resolver.example.com. ( alpn=dot ) ]]></artwork> <t>ClientsMUST<bcp14>MUST</bcp14> validate that for any Encrypted DNS Resolver discovered using a known resolver name, the TLS certificate of the resolver contains the known name in a subjectAltName extension. In the example above, this means that both servers need to have certificates that cover the name <tt>resolver.example.com</tt>. Often, the various supported encrypted DNS protocols will be specified such that the SVCB TargetName matches the known name, as is true in the example above. However, even when the TargetName is different (for example, if the DoH server had a TargetName of <tt>doh.example.com</tt>), the clients still check for the original known resolver name in the certificate.</t> <t>Note that this resolver validation is not related to the DNS resolver that provided the SVCB answer.</t> <t>As another example, being able to discover a Designated Resolver for a known Encrypted DNS Resolver is useful when a client has a DoT configuration for <tt>foo.resolver.example.com</tt> but is on a network that blocks DoT traffic. The client can still send a query to any other accessible resolver (either the local network resolver or an accessible DoH server) to discover if there is a designated DoH server for <tt>foo.resolver.example.com</tt>.</t> </section> <section anchor="deployment-considerations"> <name>Deployment Considerations</name> <t>Resolver deployments that support DDR are advised to consider the following points.</t> <section anchor="caching-forwarders"> <name>Caching Forwarders</name> <t>A DNS forwarderSHOULD NOT<bcp14>SHOULD NOT</bcp14> forward queries for "resolver.arpa" (or any subdomains) upstream. This prevents a client from receiving an SVCB record that will fail to authenticate because the forwarder's IP address is not in the upstream resolver's Designated Resolver's TLS certificateSANSubjectAlternativeName (SAN) field. A DNS forwarderwhichthat already acts as a completely transparent forwarderMAY<bcp14>MAY</bcp14> choose to forward these queries when the operator expects that this does not apply,eitherbecause the operator either knows that the upstream resolver does have the forwarder's IP address in its TLS certificate's SAN field orthat the operatorexpects clients to validate the connection via some futuremechanism.</t>mechanism. <!-- [rfced] Section 6.1: We added "SAN" after "SubjectAlternativeName" here, but we have some follow-up items for you: (a) If this definition is incorrect, please provide the correct definition. (b) Should "SubjectAlternativeName" be "SubjectAltName"? We see that RFCs 6876, 6940, and 7086 use "SubjectAltName field", but we don't see any instances of "SubjectAlternativeName field" in any recent RFCs. (c) If the "Possibly" text below is not correct, please clarify the meaning of "upstream resolver's Designated Resolver's". Original: This prevents a client from receiving an SVCB record that will fail to authenticate because the forwarder's IP address is not in the upstream resolver's Designated Resolver's TLS certificate SAN field. Currently: This prevents a client from receiving an SVCB record that will fail to authenticate because the forwarder's IP address is not in the upstream resolver's Designated Resolver's TLS certificate SubjectAlternativeName (SAN) field. Possibly: This prevents a client from receiving an SVCB record that will fail to authenticate because the forwarder's IP address is not in the TLS certificate SubjectAlternativeName (SAN) field of the upstream resolver's Designated Resolver. --> </t> <t>Operators who choose to forward queries for "resolver.arpa" upstream should note that client behavior is never guaranteed and that the use of DDR by a resolver does not communicate a requirement for clients to use the SVCB record when it cannot be verified.</t> </section> <section anchor="certificate-management"> <name>Certificate Management</name> <t>Resolver owners that support Verified Discovery will need to list valid referring IP addresses in their TLS certificates. This may pose challenges for resolvers with a large number of referring IP addresses.</t> </section> <section anchor="server-name-handling"> <name>Server Name Handling</name> <t>ClientsMUST NOT<bcp14>MUST NOT</bcp14> use "resolver.arpa" as the server nameeitherintheeither (1) the TLS Server Name Indication (SNI)(<xref target="RFC8446"/>)<xref target="RFC8446"/> for DoT, DoQ, or DoHconnections,connections orin the(2) the URI host for DoH requests.</t> <t>When performing discovery using resolver IP addresses, clientsMUST<bcp14>MUST</bcp14> use the original IP address of the Unencrypted DNS Resolver as the URI host for DoH requests.</t> <t>Note that since IP addresses are not supported by default in the TLS SNI, resolvers that support discovery using IP addresses will need to be configured to present the appropriate TLS certificate when no SNI is present for DoT, DoQ, and DoH.</t> </section> <section anchor="handling-non-ddr-queries-for-resolverarpa"> <name>Handlingnon-DDR queriesNon-DDR Queries for resolver.arpa</name> <t>DNS resolvers that support DDR by responding to queries for _dns.resolver.arpaMUST<bcp14>MUST</bcp14> treat resolver.arpa as a locally served zone per <xref target="RFC6303"/>. In practice, this means that resolversSHOULD<bcp14>SHOULD</bcp14> respond to queries of any type other than SVCB for _dns.resolver.arpa with NODATA and queries of any type for any domain name under resolver.arpa with NODATA.</t> </section> <section anchor="dnr-interaction"> <name>Interaction with Network-Designated Resolvers</name><t>Discovery of network-designated resolvers (DNR,<t>DNR <xreftarget="I-D.ietf-add-dnr"/>)target="RFC9463"/> allows a network to provide designation of resolvers directly through DHCP <xref target="RFC2132"/> <xref target="RFC8415"/> and through IPv6Router Advertisement (RA)RA options <xreftarget="RFC4861"/> options.target="RFC4861"/>. When such indications are present, clients can suppress queries for "resolver.arpa" to the unencrypted DNS server indicated by the network over DHCP or RAs, and the DNR indicationsSHOULD<bcp14>SHOULD</bcp14> take precedence over those discovered using "resolver.arpa" for the same resolver if there is a conflict, since DNR is considered a more reliable source.</t> <t>The designated resolver information in DNR might not contain a full set of SvcParams needed to connect to an encrypted DNS resolver. In such a case, the client can use an SVCB query using a resolver name, as described in <xref target="encrypted"/>, to theauthentication-domain-nameAuthentication Domain Name (ADN).</t> </section> </section> <section anchor="security"> <name>Security Considerations</name> <t>Since clients can receive DNS SVCB answers over unencrypted DNS, on-path attackers can prevent successful discovery by dropping SVCB queries oranswers,answers and thus can prevent clients from switching touseusing encrypted DNS. Clients should be aware that it might not be possible to distinguish between resolvers that do not have any Designated Resolver and such an active attack. To limit the impact of discovery queries being dropped either maliciously or unintentionally, clients can re-send their SVCB queries periodically.</t> <t><xref section="8.2" sectionFormat="of"target="I-D.ietf-add-svcb-dns"/>target="RFC9461"/> describesa secondanother type of downgrade attack where an attacker can block connections to the encrypted DNS server. For DDR, clients need to validate a Designated Resolver using a connection to the server before trusting it, so attackers that can block these connections can prevent clients from switching to using encrypted DNS. <!-- [rfced] Section 7: Should "trusting it, so" be "trusting it; otherwise," or should "can prevent clients" perhaps be "cannot prevent clients"? The sentence as written seems to indicate that the way should be paved for attackers to block the connections, when it seems that the opposite should be true. Original: For DDR, clients need to validate a Designated Resolver using a connection to the server before trusting it, so attackers that can block these connections can prevent clients from switching to use encryptedDNS.</t>DNS. --> </t> <t>Encrypted DNS Resolvers that allow discovery using DNS SVCB answers over unencrypted DNSMUST NOT<bcp14>MUST NOT</bcp14> provide differentiated behavior based solely on metadata in the SVCB record, such as the HTTP path or alternate port number, which are parameters that an attacker could modify. For example, if a DoH resolver provides a filtering service for one URIpath,path and a non-filtered service for another URI path, an attacker could select which of these services is used by modifying the "dohpath" parameter. These attacks can be mitigated by providing separate resolver IP addresses or hostnames.</t> <t>While the IP address of the Unencrypted DNS Resolver is often provisioned over insecure mechanisms, it can also be provisioned securely, such as via manual configuration, on a VPN, or on a network with protections like RA-Guard <xref target="RFC6105"/>. An attacker might try to direct Encrypted DNS traffic to itself by causing the client to think that a discovered Designated Resolver uses a different IP address from the Unencrypted DNS Resolver. Such a Designated Resolver might have a validcertificate,certificate but might be operated by an attacker that is trying to observe or modify user queries without the knowledge of the client or network.</t> <t>If the IP address of a Designated Resolver differs from that of an Unencrypted DNS Resolver, clients applying Verified Discovery (<xref target="verified"/>)MUST<bcp14>MUST</bcp14> validate that the IP address of the Unencrypted DNS Resolver is covered by the SubjectAlternativeName of the Designated Resolver's TLS certificate. If that validation fails, the clientMUST NOT<bcp14>MUST NOT</bcp14> automatically use the discovered Designated Resolver.</t> <t>Clients using Opportunistic Discovery (<xref target="opportunistic"/>)MUST<bcp14>MUST</bcp14> be limited to cases where the Unencrypted DNS Resolver and Designated Resolver have the same IP address, whichSHOULD<bcp14>SHOULD</bcp14> be a private or local IP address. Clientswhichthat do not follow Opportunistic Discovery (<xref target="opportunistic"/>) and instead try to connect without first checking for a designation run the possible risk of being intercepted by an attacker hosting an Encrypted DNS Resolver on an IP address of an Unencrypted DNS Resolver where the attacker has failed to gain control of the Unencrypted DNS Resolver.</t> <t>The constraints on the use of Designated Resolvers specified here apply specifically to the automatic discovery mechanisms defined in this document, which are referred to as Verified Discovery and Opportunistic Discovery. ClientsMAY<bcp14>MAY</bcp14> use some other mechanism to verify and use Designated Resolvers discovered using the DNS SVCB record. However, the use of such an alternate mechanism needs to take into account the attack scenarios detailed here.</t> </section> <section anchor="iana"> <name>IANA Considerations</name> <section anchor="special-use-domain-name-resolverarpa"><name>Special Use<name>Special-Use Domain Name "resolver.arpa"</name><t>This<t>IANA has registered "resolver.arpa" in the "Special-Use Domain Names" registry established by <xref target="RFC6761"/>.</t> <!--[rfced] Section 8.1: Should 'resolver.arpa.' include the final period as it appears in the IANA registry (see https://www.iana.org/assignments/special-use-domain-names)? We note that the period does not appear in the "Transport-Independent Locally-Served DNS Zone Registry" (see https://www.iana.org/assignments/locally-served-dns-zones). Original (note the final period in the second paragraph): 8.1. Special Use Domain Name "resolver.arpa" This document calls for the addition of "resolver.arpa" to the Special-Use Domain Names (SUDN) registry established by<xref target="RFC6761"/>.</t> <t>IANA[RFC6761]. IANA is requested to add an entry in "Transport-IndependentLocally-ServedLocally- Served DNS Zones" registry for 'resolver.arpa.' with the description "DNS Resolver Special-Use Domain", listing this document as the reference. If the period should be present, please consider whether any other mentions of 'resolver.arpa' should be updated. We note that the period is used consistently in RFC 8375, which registers 'home.arpa.' --> <t>IANA has added an entry in the "Transport-Independent Locally-Served DNS Zone Registry" for 'resolver.arpa.' with the description "DNS Resolver Special-Use Domain" and listed this document as the reference.</t> </section> <section anchor="domain-name-reservation-considerations"> <name>Domain Name Reservation Considerations</name> <t>In accordance with <xref section="5" sectionFormat="of" target="RFC6761"/>, the answers to the following questions are provided relative to this document:</t><t>1) Are<ol spacing="normal" type="1"> <li><t>Are human users expected to recognize these names as special and use them differently? In what way?</t> <t>No. This name is used automatically by DNS stub resolvers running on client devices on behalf of users, and users will never see this namedirectly.</t> <t>2) Aredirectly.</t></li> <li><t>Are writers of application software expected to make their software recognize these names as special and treat them differently? In what way?</t> <t>No. There is no use case where a non-DNS application (covered by the next question) would need to use thisname.</t> <t>3) Arename.</t></li> <li><t>Are writers of name resolution APIs and libraries expected to make their software recognize these names as special and treat them differently? If so, how?</t> <t>Yes.DNS DNS client implementors are expected to use this name when querying for a resolver's properties instead of records for the name itself. DNS servers are expected to respond to queries for this name with their own properties instead of checking the matching zone as it would for normal domainnames.</t> <t>4) Arenames.</t></li> <li><t>Are developers of caching domain name servers expected to make their implementations recognize these names as special and treat them differently? If so, how?</t> <t>Yes.Caching Caching domain name servers should not forward queries for thisnamename, to avoid causing validation failures due to IP addressmismatch.</t> <t>5) Aremismatch.</t></li> <li><t>Are developers of authoritative domain name servers expected to make their implementations recognize these names as special and treat them differently? If so, how?</t> <t>No. DDR is designed for use by recursive resolvers. Theoretically, an authoritative server could choose to support this name if it wants to advertise support for encrypted DNS protocols overplain-textplaintext DNS, but that scenario is covered by other work in the IETF DNSOPworking group.</t> <t>6) DoesWorking Group.</t></li> <li><t>Does this reserved Special-Use Domain Name have any potential impact on DNS server operators? If they try to configure their authoritative DNS server as authoritative for this reserved name, will compliant name server software reject it as invalid? Do DNS server operators need to know about that and understand why? Even if the name server software doesn't prevent them from using this reserved name, are there other ways that it may not work as expected, of which the DNS server operator should be aware?</t> <t>This name is locally served, and any resolverwhichthat supports this name should never forward the query. DNS server operators should be aware that records for this name will be used by clients to modify the way they connect to theirresolvers.</t> <t>7) Howresolvers.</t></li> <li><t>How should DNS Registries/Registrars treat requests to register this reserved domain name? Should such requests be denied? Should such requests be allowed, but only to aspecially-designatedspecially designated entity?</t> <t>IANAshould holdholds the registration for this name. Non-IANA requests to register this name should always be denied by DNSRegistries/Registrars.</t> </section> </section> </middle> <back> <references> <name>References</name> <references> <name>Normative References</name> <reference anchor="RFC7858"> <front> <title>Specification for DNS over Transport Layer Security (TLS)</title> <author fullname="Z. Hu" initials="Z." surname="Hu"> <organization/> </author> <author fullname="L. Zhu" initials="L." surname="Zhu"> <organization/> </author> <author fullname="J. Heidemann" initials="J." surname="Heidemann"> <organization/> </author> <author fullname="A. Mankin" initials="A." surname="Mankin"> <organization/> </author> <author fullname="D. Wessels" initials="D." surname="Wessels"> <organization/> </author> <author fullname="P. Hoffman" initials="P." surname="Hoffman"> <organization/> </author> <date month="May" year="2016"/> <abstract> <t>This document describes the use of Transport Layer Security (TLS)Registries/Registrars.</t></li> </ol> <!-- [rfced] Section 8.2: We see that Questions 1 through 5 refer toprovide privacy for DNS. Encryption provided by TLS eliminates opportunities for eavesdropping"these names" but Questions 6 andon-path tampering with DNS queries7 refer to "name" in thenetwork, such as discussed in RFC 7626. In addition,singular (e.g., "this reserved name", "this reserved domain name"). Although we also see thisdocument specifies two usage profiles for DNS over TLS and provides advice on performance considerations to minimize overhead from using TCP and TLS with DNS.</t> <t>This document focuses on securing stub-to-recursive traffic, as per the charter of the DPRIVE Working Group. It does not prevent future applications of the protocol to recursive-to-authoritative traffic.</t> </abstract> </front> <seriesInfo name="RFC" value="7858"/> <seriesInfo name="DOI" value="10.17487/RFC7858"/> </reference> <reference anchor="RFC9250"> <front> <title>DNS over Dedicated QUIC Connections</title> <author fullname="C. Huitema" initials="C." surname="Huitema"> <organization/> </author> <author fullname="S. Dickinson" initials="S." surname="Dickinson"> <organization/> </author> <author fullname="A. Mankin" initials="A." surname="Mankin"> <organization/> </author> <date month="May" year="2022"/> <abstract> <t>This document describes the use of QUIC to provide transport confidentiality for DNS. The encryption provided by QUIC has similar propertiesswitch tothose provided by TLS, while QUIC transport eliminatesthehead-of-line blocking issues inherent with TCP and provides more efficient packet-loss recovery than UDP. DNS over QUIC (DoQ) has privacy properties similar to DNS over TLS (DoT) specifiedsingular inRFC 7858,Questions 6 andlatency characteristics similar to classic DNS over UDP. This specification describes the use7 in Section 5 ofDoQ as a general-purpose transport for DNS and includesRFC 6761, we suggest using theuse of DoQ for stub to recursive, recursive to authoritative, and zone transfer scenarios.</t> </abstract> </front> <seriesInfo name="RFC" value="9250"/> <seriesInfo name="DOI" value="10.17487/RFC9250"/> </reference> <reference anchor="RFC8484"> <front> <title>DNS Queries over HTTPS (DoH)</title> <author fullname="P. Hoffman" initials="P." surname="Hoffman"> <organization/> </author> <author fullname="P. McManus" initials="P." surname="McManus"> <organization/> </author> <date month="October" year="2018"/> <abstract> <t>This document defines a protocol for sending DNS queries and getting DNS responses over HTTPS. Each DNS query-response pair is mapped into an HTTP exchange.</t> </abstract> </front> <seriesInfo name="RFC" value="8484"/> <seriesInfo name="DOI" value="10.17487/RFC8484"/> </reference> <reference anchor="RFC6761"> <front> <title>Special-Use Domain Names</title> <author fullname="S. Cheshire" initials="S." surname="Cheshire"> <organization/> </author> <author fullname="M. Krochmal" initials="M." surname="Krochmal"> <organization/> </author> <date month="February" year="2013"/> <abstract> <t>This document describes what it means to say that a Domain Name (DNS name) is reserved for special use, when reserving suchplural "names" in all questions. Please let us know your preference. --> </section> <!--[rfced] Section 8: Should aname is appropriate, and the procedure for doing so. It establishes ansubsection be added as follows regarding IANA's Action 3? 8.3. .ARPA Zone Management IANAregistry for such domain names, and seeds it with entries for some ofhas added thealready established special domain names.</t> </abstract> </front> <seriesInfo name="RFC" value="6761"/> <seriesInfo name="DOI" value="10.17487/RFC6761"/> </reference> <reference anchor="RFC2119"> <front> <title>Key words for use in RFCs to Indicate Requirement Levels</title> <author fullname="S. Bradner" initials="S." surname="Bradner"> <organization/> </author> <date month="March" year="1997"/> <abstract> <t>In many standards track documents several words are usedfollowing entry tosignifytherequirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t> </abstract> </front> <seriesInfo name="BCP" value="14"/> <seriesInfo name="RFC" value="2119"/> <seriesInfo name="DOI" value="10.17487/RFC2119"/> </reference> <reference anchor="RFC8174"> <front> <title>Ambiguity".ARPA Zone Management" list. resolver.arpa For discovery ofUppercase vs Lowercase indesignated DNS resolvers RFC2119 Key Words</title> <author fullname="B. Leiba" initials="B." surname="Leiba"> <organization/> </author> <date month="May" year="2017"/> <abstract> <t>RFC 2119 specifies common key words that may be used in protocol specifications. This document aims9462 For background, mail from IANA (2 Sep 2022): ACTION 3: The following entry has been added toreduce the ambiguity by clarifying that only UPPERCASE usageIANA's .ARPA Zone Management list: resolver.arpa For discovery ofthe key words have the defined special meanings.</t> </abstract> </front> <seriesInfo name="BCP" value="14"/> <seriesInfo name="RFC" value="8174"/> <seriesInfo name="DOI" value="10.17487/RFC8174"/> </reference>designated DNS resolvers draft-ietf-add-ddr-10 Please see https://www.iana.org/domains/arpa --> </section> </middle> <back> <displayreference target="I-D.schinazi-httpbis-doh-preference-hints" to="DoH-HINTS"/> <displayreference target="I-D.ietf-tls-esni" to="ECH"/> <references> <name>References</name> <references> <name>Normative References</name> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7858.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9250.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8484.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6761.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/> <!-- draft-ietf-dnsop-svcb-https (RFC 9460) --> <referenceanchor="I-D.ietf-dnsop-svcb-https">anchor='RFC9460' target='https://www.rfc-editor.org/info/rfc9460'> <front> <title>ServicebindingBinding andparameter specificationParameter Specification via the DNS (DNS SVCB and HTTPSRRs)</title> <author fullname="Ben Schwartz"> <organization>Google</organization> </author> <author fullname="Mike Bishop"> <organization>Akamai Technologies</organization> </author> <author fullname="Erik Nygren"> <organization>Akamai Technologies</organization>Resource Records (RRs))</title> <author initials='B' surname='Schwartz' fullname='Benjamin Schwartz'> <organization /> </author> <author initials='M' surname='Bishop' fullname='Mike Bishop'> <organization /> </author> <author initials='E' surname='Nygren' fullname='Erik Nygren'> <organization /> </author> <dateday="24" month="May" year="2022"/> <abstract> <t> This document specifies the "SVCB" and "HTTPS" DNS resource record (RR) types to facilitate the lookup of information needed to make connections to network services, such as for HTTP origins. SVCB records allow a service to be provided from multiple alternative endpoints, each with associated parameters (such as transport protocol configuration and keys for encrypting the TLS ClientHello). They also enable aliasing of apex domains, which is not possible with CNAME. The HTTPS RR is a variation of SVCB for use with HTTP [HTTP]. By providing more information to the client before it attempts to establish a connection, these records offer potential benefits to both performance and privacy. TO BE REMOVED: This document is being collaborated on in Github at: https://github.com/MikeBishop/dns-alt-svc (https://github.com/MikeBishop/dns-alt-svc). The most recent working version of the document, open issues, etc. should all be available there. The authors (gratefully) accept pull requests. </t> </abstract>month="September" year="2023"/> </front> <seriesInfoname="Internet-Draft" value="draft-ietf-dnsop-svcb-https-10"/>name="RFC" value="9460"/> <seriesInfo name="DOI" value="10.17487/RFC9460"/> </reference> <!-- draft-ietf-add-svcb-dns (RFC 9461) --> <referenceanchor="I-D.ietf-add-svcb-dns">anchor='RFC9461' target='https://www.rfc-editor.org/info/rfc9461'> <front> <title>Service Binding Mapping for DNS Servers</title> <author initials="B." surname="Schwartz" fullname="Benjamin Schwartz"><organization>Google LLC</organization> </author> <date day="5" month="July" year="2022"/> <abstract> <t> The SVCB DNS resource record type expresses a bound collection of endpoint metadata, for use when establishing a connection to a named service. DNS itself can be such a service, when the server is identified by a domain name. This document provides the SVCB mapping for named DNS servers, allowing them to indicate support for encrypted transport protocols. </t> </abstract> </front> <seriesInfo name="Internet-Draft" value="draft-ietf-add-svcb-dns-06"/> </reference> <reference anchor="RFC5280"> <front> <title>Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile</title> <author fullname="D. Cooper" initials="D." surname="Cooper"> <organization/> </author> <author fullname="S. Santesson" initials="S." surname="Santesson"> <organization/> </author> <author fullname="S. Farrell" initials="S." surname="Farrell"> <organization/> </author> <author fullname="S. Boeyen" initials="S." surname="Boeyen"> <organization/> </author> <author fullname="R. Housley" initials="R." surname="Housley"> <organization/> </author> <author fullname="W. Polk" initials="W." surname="Polk"> <organization/> </author> <date month="May" year="2008"/> <abstract> <t>This memo profiles the X.509 v3 certificate and X.509 v2 certificate revocation list (CRL) for use in the Internet. An overview of this approach and model is provided as an introduction. The X.509 v3 certificate format is described in detail, with additional information regarding the format and semantics of Internet name forms. Standard certificate extensions are described and two Internet-specific extensions are defined. A set of required certificate extensions is specified. The X.509 v2 CRL format is described in detail along with standard and Internet-specific extensions. An algorithm for X.509 certification path validation is described. An ASN.1 module and examples are provided in the appendices. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="5280"/> <seriesInfo name="DOI" value="10.17487/RFC5280"/> </reference> <reference anchor="RFC1918"> <front> <title>Address Allocation for Private Internets</title> <author fullname="Y. Rekhter" initials="Y." surname="Rekhter"> <organization/> </author> <author fullname="B. Moskowitz" initials="B." surname="Moskowitz"> <organization/> </author> <author fullname="D. Karrenberg" initials="D." surname="Karrenberg"> <organization/> </author> <author fullname="G. J. de Groot" initials="G. J." surname="de Groot"> <organization/> </author> <author fullname="E. Lear" initials="E." surname="Lear"> <organization/></author> <datemonth="February" year="1996"/> <abstract> <t>This document describes address allocation for private internets. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t> </abstract> </front> <seriesInfo name="BCP" value="5"/> <seriesInfo name="RFC" value="1918"/> <seriesInfo name="DOI" value="10.17487/RFC1918"/> </reference> <reference anchor="RFC4193"> <front> <title>Unique Local IPv6 Unicast Addresses</title> <author fullname="R. Hinden" initials="R." surname="Hinden"> <organization/> </author> <author fullname="B. Haberman" initials="B." surname="Haberman"> <organization/> </author> <date month="October" year="2005"/> <abstract> <t>This document defines an IPv6 unicast address format that is globally unique and is intended for local communications, usually inside of a site. These addresses are not expected to be routable on the global Internet. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="4193"/> <seriesInfo name="DOI" value="10.17487/RFC4193"/> </reference> <reference anchor="RFC3927"> <front> <title>Dynamic Configuration of IPv4 Link-Local Addresses</title> <author fullname="S. Cheshire" initials="S." surname="Cheshire"> <organization/> </author> <author fullname="B. Aboba" initials="B." surname="Aboba"> <organization/> </author> <author fullname="E. Guttman" initials="E." surname="Guttman"> <organization/> </author> <date month="May" year="2005"/> <abstract> <t>To participate in wide-area IP networking, a host needs to be configured with IP addresses for its interfaces, either manually by the user or automatically from a source on the network such as a Dynamic Host Configuration Protocol (DHCP) server. Unfortunately, such address configuration information may not always be available. It is therefore beneficial for a host to be able to depend on a useful subset of IP networking functions even when no address configuration is available. This document describes how a host may automatically configure an interface with an IPv4 address within the 169.254/16 prefix that is valid for communication with other devices connected to the same physical (or logical) link.</t> <t>IPv4 Link-Local addresses are not suitable for communication with devices not directly connected to the same physical (or logical) link, and are only used where stable, routable addresses are not available (such as on ad hoc or isolated networks). This document does not recommend that IPv4 Link-Local addresses and routable addresses be configured simultaneously on the same interface. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="3927"/> <seriesInfo name="DOI" value="10.17487/RFC3927"/> </reference> <reference anchor="RFC4291"> <front> <title>IP Version 6 Addressing Architecture</title> <author fullname="R. Hinden" initials="R." surname="Hinden"> <organization/> </author> <author fullname="S. Deering" initials="S." surname="Deering"> <organization/> </author> <date month="February" year="2006"/> <abstract> <t>This specification defines the addressing architecture of the IP Version 6 (IPv6) protocol. The document includes the IPv6 addressing model, text representations of IPv6 addresses, definition of IPv6 unicast addresses, anycast addresses, and multicast addresses, and an IPv6 node's required addresses.</t> <t>This document obsoletes RFC 3513, "IP Version 6 Addressing Architecture". [STANDARDS-TRACK]</t> </abstract>month="September" year="2023"/> </front> <seriesInfo name="RFC"value="4291"/>value="9461"/> <seriesInfo name="DOI"value="10.17487/RFC4291"/>value="10.17487/RFC9461"/> </reference> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5280.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.1918.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4193.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.3927.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4291.xml"/> <!-- draft-ietf-add-dnr (RFC 9463) --> <referenceanchor="I-D.ietf-add-dnr">anchor='RFC9463' target='https://www.rfc-editor.org/info/rfc9463'> <front><title>DHCP<title> DHCP and Router Advertisement Options for the Discovery of Network-designated Resolvers(DNR)</title>(DNR) </title> <author initials="M." surname="Boucadair" fullname="MohamedBoucadair"> <organization>Orange</organization>Boucadair" role="editor"> </author> <author initials="T." surname="Reddy.K" fullname="TirumaleswarReddy"> <organization>Akamai</organization>Reddy.K" role="editor"> </author> <author initials="D." surname="Wing" fullname="Dan Wing"><organization>Citrix Systems, Inc.</organization></author> <author initials="N." surname="Cook" fullname="Neil Cook"><organization>Open-Xchange</organization></author> <author initials="T." surname="Jensen" fullname="Tommy Jensen"><organization>Microsoft</organization></author> <dateday="24" month="July" year="2022"/> <abstract> <t> The document specifies new DHCP and IPv6 Router Advertisement options to discover encrypted DNS resolvers (e.g., DNS-over-HTTPS, DNS-over- TLS, DNS-over-QUIC). Particularly, it allows a host to learn an authentication domain name together with a list of IP addresses and a set of service parameters to reach such encrypted DNS resolvers. </t> </abstract> </front> <seriesInfo name="Internet-Draft" value="draft-ietf-add-dnr-12"/> </reference> <reference anchor="RFC6303"> <front> <title>Locally Served DNS Zones</title> <author fullname="M. Andrews" initials="M." surname="Andrews"> <organization/> </author> <date month="July" year="2011"/> <abstract> <t>Experience with the Domain Name System (DNS) has shown that there are a number of DNS zones that all iterative resolvers and recursive nameservers should automatically serve, unless configured otherwise. RFC 4193 specifies that this should occur for D.F.IP6.ARPA. This document extends the practice to cover the IN-ADDR.ARPA zones for RFC 1918 address space and other well-known zones with similar characteristics. This memo documents an Internet Best Current Practice.</t> </abstract>month="September" year="2023"/> </front> <seriesInfoname="BCP" value="163"/> <seriesInfoname="RFC"value="6303"/>value="9463"/> <seriesInfo name="DOI"value="10.17487/RFC6303"/>value="10.17487/RFC9463"/> </reference> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6303.xml"/> </references> <references> <name>Informative References</name><reference anchor="RFC2132"> <front> <title>DHCP Options and BOOTP Vendor Extensions</title> <author fullname="S. Alexander" initials="S." surname="Alexander"> <organization/> </author> <author fullname="R. Droms" initials="R." surname="Droms"> <organization/> </author> <date month="March" year="1997"/> <abstract> <t>This document specifies the current set of DHCP options. Future options will be specified in separate RFCs. The current list of valid options is also available in ftp://ftp.isi.edu/in-notes/iana/assignments. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="2132"/> <seriesInfo name="DOI" value="10.17487/RFC2132"/> </reference> <reference anchor="RFC8415"> <front> <title>Dynamic Host Configuration Protocol for IPv6 (DHCPv6)</title> <author fullname="T. Mrugalski" initials="T." surname="Mrugalski"> <organization/> </author> <author fullname="M. Siodelski" initials="M." surname="Siodelski"> <organization/> </author> <author fullname="B. Volz" initials="B." surname="Volz"> <organization/> </author> <author fullname="A. Yourtchenko" initials="A." surname="Yourtchenko"> <organization/> </author> <author fullname="M. Richardson" initials="M." surname="Richardson"> <organization/> </author> <author fullname="S. Jiang" initials="S." surname="Jiang"> <organization/> </author> <author fullname="T. Lemon" initials="T." surname="Lemon"> <organization/> </author> <author fullname="T. Winters" initials="T." surname="Winters"> <organization/> </author> <date month="November" year="2018"/> <abstract> <t>This document describes the Dynamic Host Configuration Protocol for IPv6 (DHCPv6): an extensible mechanism for configuring nodes with network configuration parameters, IP addresses, and prefixes. Parameters can be provided statelessly, or in combination with stateful assignment of one or more IPv6 addresses and/or IPv6 prefixes. DHCPv6 can operate either in place of or in addition to stateless address autoconfiguration (SLAAC).</t> <t>This document updates the text from RFC 3315 (the original DHCPv6 specification) and incorporates prefix delegation (RFC 3633), stateless DHCPv6 (RFC 3736), an option to specify an upper bound for how long a client should wait before refreshing information (RFC 4242), a mechanism for throttling DHCPv6 clients when DHCPv6 service is not available (RFC 7083), and relay agent handling of unknown messages (RFC 7283). In addition, this document clarifies the interactions between models of operation (RFC 7550). As such, this document obsoletes RFC 3315, RFC 3633, RFC 3736, RFC 4242, RFC 7083, RFC 7283, and RFC 7550.</t> </abstract> </front> <seriesInfo name="RFC" value="8415"/> <seriesInfo name="DOI" value="10.17487/RFC8415"/> </reference> <reference anchor="RFC8106"> <front> <title>IPv6 Router Advertisement Options for DNS Configuration</title> <author fullname="J. Jeong" initials="J." surname="Jeong"> <organization/> </author> <author fullname="S. Park" initials="S." surname="Park"> <organization/> </author> <author fullname="L. Beloeil" initials="L." surname="Beloeil"> <organization/> </author> <author fullname="S. Madanapalli" initials="S." surname="Madanapalli"> <organization/> </author> <date month="March" year="2017"/> <abstract> <t>This document specifies IPv6 Router Advertisement (RA) options (called "DNS RA options") to allow IPv6 routers to advertise a list of DNS Recursive Server Addresses and a DNS Search List to IPv6 hosts.</t> <t>This document, which obsoletes RFC 6106, defines a higher default value of the lifetime of the DNS RA options to reduce the likelihood of expiry of the options on links with a relatively high rate of packet loss.</t> </abstract> </front> <seriesInfo name="RFC" value="8106"/> <seriesInfo name="DOI" value="10.17487/RFC8106"/> </reference> <reference anchor="RFC8446"> <front> <title>The Transport Layer Security (TLS) Protocol Version 1.3</title> <author fullname="E. Rescorla" initials="E." surname="Rescorla"> <organization/> </author> <date month="August" year="2018"/> <abstract> <t>This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery.</t> <t>This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations.</t> </abstract> </front> <seriesInfo name="RFC" value="8446"/> <seriesInfo name="DOI" value="10.17487/RFC8446"/> </reference> <reference anchor="RFC4861"> <front> <title>Neighbor Discovery for IP version 6 (IPv6)</title> <author fullname="T. Narten" initials="T." surname="Narten"> <organization/> </author> <author fullname="E. Nordmark" initials="E." surname="Nordmark"> <organization/> </author> <author fullname="W. Simpson" initials="W." surname="Simpson"> <organization/> </author> <author fullname="H. Soliman" initials="H." surname="Soliman"> <organization/> </author> <date month="September" year="2007"/> <abstract> <t>This document specifies the Neighbor Discovery protocol for IP Version 6. IPv6 nodes on the same link use Neighbor Discovery to discover each other's presence, to determine each other's link-layer addresses, to find routers, and to maintain reachability information about the paths to active neighbors. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="4861"/> <seriesInfo name="DOI" value="10.17487/RFC4861"/> </reference> <reference anchor="RFC6105"> <front> <title>IPv6 Router Advertisement Guard</title> <author fullname="E. Levy-Abegnoli" initials="E." surname="Levy-Abegnoli"> <organization/> </author> <author fullname="G. Van de Velde" initials="G." surname="Van de Velde"> <organization/> </author> <author fullname="C. Popoviciu" initials="C." surname="Popoviciu"> <organization/> </author> <author fullname="J. Mohacsi" initials="J." surname="Mohacsi"> <organization/> </author> <date month="February" year="2011"/> <abstract> <t>Routed protocols are often susceptible to spoof attacks. The canonical solution for IPv6 is Secure Neighbor Discovery (SEND), a solution that is non-trivial to deploy. This document proposes a light-weight alternative and complement to SEND based on filtering in the layer-2 network fabric, using a variety of filtering criteria, including, for example, SEND status. This document is not an Internet Standards Track specification; it is published for informational purposes.</t> </abstract> </front> <seriesInfo name="RFC" value="6105"/> <seriesInfo name="DOI" value="10.17487/RFC6105"/> </reference> <reference anchor="RFC8880"> <front> <title>Special Use Domain Name 'ipv4only.arpa'</title> <author fullname="S. Cheshire" initials="S." surname="Cheshire"> <organization/> </author> <author fullname="D. Schinazi" initials="D." surname="Schinazi"> <organization/> </author> <date month="August" year="2020"/> <abstract> <t>NAT64 (Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers) allows client devices using IPv6 to communicate with servers that have only IPv4 connectivity.</t> <t>The specification for how a client discovers its local network's NAT64 prefix (RFC 7050) defines the special name 'ipv4only.arpa' for this purpose. However, in its Domain Name Reservation Considerations section (Section 8.1), that specification (RFC 7050) indicates that the name actually has no particularly special properties that would require special handling.</t> <t>Consequently, despite the well-articulated special purpose of the name, 'ipv4only.arpa' was not recorded in the Special-Use Domain Names registry as a name with special properties.</t> <t>This document updates RFC 7050. It describes the special treatment required and formally declares the special properties of the name. It also adds similar declarations for the corresponding reverse mapping names.</t> </abstract> </front> <seriesInfo name="RFC" value="8880"/> <seriesInfo name="DOI" value="10.17487/RFC8880"/> </reference> <reference anchor="I-D.schinazi-httpbis-doh-preference-hints"> <front> <title>DoH Preference Hints for HTTP</title> <author fullname="David Schinazi"> <organization>Google LLC</organization> </author> <author fullname="Nick Sullivan"> <organization>Cloudflare</organization> </author> <author fullname="Jesse Kipp"> <organization>Cloudflare</organization> </author> <date day="13" month="July" year="2020"/> <abstract> <t> When using a publicly available DNS-over-HTTPS (DoH) server, some clients may suffer poor performance when the authoritative DNS server is located far from the DoH server. For example, a publicly available DoH server provided by a Content Delivery Network (CDN) should be able to resolve names hosted by that CDN with good performance but might take longer to resolve names provided by other CDNs, or might provide suboptimal results if that CDN is using DNS- based load balancing and returns different address records depending or where the DNS query originated from. This document attempts to lessen these issues by allowing the web server to indicate to the client which DoH server can best resolve its addresses. This document defines an HTTP header field that enables web host operators to inform user agents of the preferred DoH servers to use for subsequent DNS lookups for the host's domain. Discussion of this work is encouraged to happen on the ADD IETF mailing list add@ietf.org or on the GitHub repository which contains the draft: https://github.com/DavidSchinazi/draft-httpbis-doh- preference-hints. </t> </abstract> </front> <seriesInfo name="Internet-Draft" value="draft-schinazi-httpbis-doh-preference-hints-02"/> </reference> <reference anchor="I-D.ietf-tls-esni"> <front> <title>TLS Encrypted Client Hello</title> <author fullname="Eric Rescorla"> <organization>RTFM, Inc.</organization> </author> <author fullname="Kazuho Oku"> <organization>Fastly</organization> </author> <author fullname="Nick Sullivan"> <organization>Cloudflare</organization> </author> <author fullname="Christopher A. Wood"> <organization>Cloudflare</organization> </author> <date day="13" month="February" year="2022"/> <abstract> <t> This document describes a mechanism in Transport Layer Security (TLS) for encrypting a ClientHello message under a server public key. Discussion Venues This note is to be removed before publishing as an RFC. Source for this draft and an issue tracker can be found at https://github.com/tlswg/draft-ietf-tls-esni (https://github.com/tlswg/draft-ietf-tls-esni). </t> </abstract> </front> <seriesInfo name="Internet-Draft" value="draft-ietf-tls-esni-14"/> </reference><xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2132.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8415.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8106.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8446.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4861.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6105.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8880.xml"/> <!-- draft-schinazi-httpbis-doh-preference-hints (Expired) --> <xi:include href="https://bib.ietf.org/public/rfc/bibxml3/reference.I-D.schinazi-httpbis-doh-preference-hints.xml"/> <!-- draft-ietf-tls-esni (I-D Exists) --> <xi:include href="https://bib.ietf.org/public/rfc/bibxml3/reference.I-D.ietf-tls-esni.xml"/> </references> </references> <section anchor="rationale-for-using-a-special-use-domain-name"> <name>Rationale forusingUsing aSpecial UseSpecial-Use Domain Name</name> <t>The "resolver.arpa" SUDN is similar to "ipv4only.arpa" in that the querying client is not interested in an answer from the authoritative "arpa" name servers. The intent of the SUDN is to allow clients to communicate with the Unencrypted DNS Resolver much like "ipv4only.arpa" allows for client-to-middlebox communication. For more context, see <xref target="RFC8880"/> for the rationale behind"ipv4only.arpa" in <xref target="RFC8880"/>.</t>"ipv4only.arpa".</t> </section> <section anchor="rationale"> <name>Rationale forusingUsing SVCBrecords</name>Records</name> <t>This mechanism uses SVCB/HTTPS resource records <xreftarget="I-D.ietf-dnsop-svcb-https"/>target="RFC9460"/> to communicate that a given domain designates a particular Designated Resolver for clients to use in place of an Unencrypted DNS Resolver (using a SUDN) or another Encrypted DNS Resolver (using its domain name).</t> <t>There are various other proposals for how to provide similar functionality. There are several reasons that this mechanism has chosen SVCB records:</t> <ul spacing="normal"> <li>Discovering encrypted DNS resolvers using DNS records keeps client logic for DNS self-contained and allows a DNS resolver operator to define which resolver names and IP addresses are related to one another.</li> <li>Using DNS records also does not rely on bootstrapping with higher-level application operations (such as those discussed in <xref target="I-D.schinazi-httpbis-doh-preference-hints"/>).</li> <li>SVCB records are extensible and allow the definition of parameterkeys. This makeskeys, making them a superior mechanism for extensibility as compared to approaches such as overloading TXT records. The same keys can be used for discovering Designated Resolvers of different transport types as well as those advertised by Unencrypted DNS Resolvers or another Encrypted DNS Resolver.</li> <li>Clients and servers that are interested in privacy of names will already need to support SVCB records in order to useEncryptedthe TLSClient HelloEncrypted ClientHello <xref target="I-D.ietf-tls-esni"/>. Without encrypting names in TLS, the value of encrypting DNS is reduced, so pairing the solutions provides thelargestgreatest benefit.</li> </ul> </section> </back> <!--##markdown-source: H4sIAAAAAAAAA81d63PbSHL/Pn8FIn9YqYrkWX6t7asrr872xkpsWSfJt7mk UtkhMBRxAgEuBpDMc/n+9vRrXiBI27e51KaSrEwC8+jp56+7h9PpVHVlV5nn 2cGr0ubNrWk3WbPIXhlbXte6M0V2YWxTwef2QOn5vDW3z7NXry5U0eS1XsGL RasX3bQ03WKqi2JaFO30+L4q4N3nKof/f920m+eZ7QqlynX7POva3nYP7t9/ dv+B0q3Rz7PTujNtbTp117Q3123Tr59nJ69eKWU7XRf/o6umhnk2xqp1+Tz7 r67JJ5lt2q41Cwt/bVb4x38rpftu2bTPVZZN4f+yrKzt8+xqlp3rvtrQJ7zi q2a12kSfNu01TLheVwaWks/oMwujm+559r428tW5bm+ynzS/kpcdbOplvzZt V9bNJHupq3LRtHWps2eP7x8/4qeavu5w9x/qEkl52QE9LNL3ZGXaMtf0lFnp sgK6rHFBP2icbJY3q3Qbr2fZv5d1bXQbbeQ1jJF8/NvYibnhJe3ay8tZdjLL fmqaItrLy2Vb2q5ZL02bfEtbelk1fbGogF2SLR3fP4bDvKutqXFJ0X4udZ39 2Oo6R6b+9h3k+u6HpdHrsr6el52dIXMmWzifZe/yd7rubbSFc93BQDfJN7T8 H7XthNdkglW+wkd+KPr8xjb19TaRgG//zeDOthg3+phGf1fmbWObRZdwU/NX eOyHlfuOJlDT6TTTcyCfzjulrpalzUCO+5Wpu6wwi7IGinxRD2SHIP9Hk0yr lcmXui7tKgOGyV6dXWZ5VcJYFqbPemvoo9bkTVvQR4UMnWn4lEf7zmamztvN GqZQNEJTL8rrvtVd2dTAKHX4XobjF/1g8HlZZx3uBWhawzfwF2gE08JXCmbV FuY7GNnJwSwjEoRt5MA2c4NLL3C9Kxg/W7TNKuvrdJXwZbqsu6Wps6auNrAS EL7zDHQhLJUYLOwWl3ZTA8duzVxaVdAKeWZYRFWuiFHhX7m2cDAwRWvilST0 gE2CEMDkJZDG71VFX8PLDUg5kWDO67TAVrARMAFw2i3Qnh8AtudPS2Nn2WlH dNGVbRxxVHyYtl+vQRsTD6RrW7cNKOumskwenBEZmWiy81w9iZhdV2VRVEap e2gm2gYEBhlDqZ9wxJjl7kq7dHy3axm2z5fID/DpFNc+vXp7CezcXB2pT5/+ 5eLHl98/ffz08+dJeOBPH05f4hN/Osr4iWcPHt/HJ5jh+aE3V1fnNM4b99TT R08fwVMKtrwh6rXml76EEwC2KHEDugKuBYqtiM+BrpuGj2/AO/gJ7sGaFmaa KLcD/DySoWVjOyQtSGWFxhQOORrIgJmsm3pK9lS3RYbnZXEP6sPFadaZ1bpC bTjL3jR3BucBVlitYF2JNAZ2tczqQNjbsjCDxahoB0XfIjMNhPoSNxENVtZ5 1cM4oGbRBeBxLTyK7/rTU1V5A8R48/IciPwCiPzg+OGDz5/lH08fHT+Gf6AQ nJ7fPskumr5DU1LcomGzhnTc4cXJEQgBrsK6947vP8GTApremapC2qJqhvNJ F71LXcKK462gEERK0AvJqEh2S9158QEiJpwbuLa3SIfABdkl/KfMjfpjWRf4 1eHln1/+cQIbOp2+mpEnVtS2WU/tbT6fLrtubT9/PnKK+LlSx2Bfvb4C5hyo qxpsZCpBF0PhnNCZ80bVLz0YUINa1q5NXgLpUAaLBixRzQJ/ePnh1ZmTjSff PzmGk4qpg3PgHpQzFtraBkbC+e/KbgkrNShxqwZE6PXo0lgkBgtXfuFLONdw BnRMuEjSS7ECwyFlCOR4UMsoucbiS4efPs2bpkPzuUbXAIgKbPFAiInTOzEU Mo6vdJSImUyDZqADC25RRaNfg+erMyTxhhaoPbHkQMWUDEyXI60K+mC3UqTt s1XQvDSnb5DoMJoIul9bmRg12jEswYutG8rJMxDOT85E+2ODh7oQpgdyto3O l8hDVdXcxRJEUtiuWFZ0bPVfj590mRy0GLqmLa9LULpOackq3RZmsX9wAPpI kT8Bc3fmYwfyrWuR1ljVfY1NVWM29fdsKz9q0LtmMjKmznMQxnIOznpT+1Ej xcoHQw5BiYKXo5JblBhv8Tpx6SB+dmhSFvyecgTxtML1eXKAub2XXaIw05go CXBYF2zDUP1ZVIcmuwHrdkcCe/Duw+XVwYT/m529p78vXoP5vHj9Cv++fHPy 9q3/g59Q8I/3H97K9/hXePPl+3fvXp+94pfh02zw0buTv8B/QN2rg/fnV6fv z07eHnhH0GtpJCa7UyUGmevW4EmxLsjbcs7O4x/BpECgw+rpwfHxM7IqZMeP vwc7TmqCJmOVSf9k2w6sC5EODgLMBUK4LjtwlCY4hV2iIOEZIT2zK9OuIMCq muvNTlsCJF00KAF4GrDeFWpr8Lafq+df9stn8OeCFGFDI0VWiSco1JA+sLCR kXC2E88ME5AYY/uVnrOxGFdqk4HQ6bpB9vSjKKdxYQkQUWVIGnA6ciPqy7Mh Oh2syuAtYD9nAdBTi7jcwtLHV8KrT1xKNqC63gx0ICjy2qLuk0WIHwKC30Pw AJYtIqF3HZs34B42V8wO4BjSWTvXYdF3fRuTHpa5y5juXmhYGO0dPJnIJk2y JQbKGLKCOlNXwLtA2g+vzsmryx4/JG4jI8FuQubchAs2rkqlcQM5985NSizt aPSH6kWtNLLhIvL+yY6HjeL+a1NxVIJSiAqpBd5OFaViRTkTf147a+jUvB1d wwRYKKtA7mqbeNFyRopG91YtWDpcC7m+/rzDu85+FawShHbvGrB6QzqSu+X9 Ke82XJLJtOSCw5ldL7OTqtQWh4jttVVbphq+6GKbR4GSMbiUaB3xIBnYFNRX exw+3COqE9wgaXdvbmUdE+F30jVgEjCc6esSXI1srVs4nA7p7/j+oGiWa90t UenCcYpGwbOMl4EIIC0C1gNLYCsRVBraqtoZPnGS4l2JVmYhAElzDm+w+gom JGcIn0HK//w/MNVMhkSg5mdQmX//+9/V8PNZln3/4P79LDs94zmPs+TbQ4JP 4PDW9R+WDzLZ7h9+B8NMacZPL3BT2RGN/us2dvVP3ljRdPETyd7gOxKCPzx9 /PD+/8lu/vRP380ve3bzy/ZuThfZqq+6Elc/qsPIx7oFVxaMGjhgrHYjzad2 +MqprwZ0WFfNhkw4yjSqB/LANJpMUI4wiuHBSSWt2xLUNriFYNWqAtVPZsDr TUi7N4ab0daioAEmQFiTtoRha6HBMGyC+JJfkp4daM6iARMH9ln1dQGvIihA GtW5bmSnyYuUd1LoboSiE5oox4c17FmRxf706dIQWJM9RR76kqpSsiekpO3K iqNI50Wwqi2DM4ynsIYw3mAwEpEEXw/7UuiVseIr2zEKOVNAcYe33+H4wxGj Zla2RMbStWl6C+6QM37BxJhbMGMUHl2X+KesqiSCZ/qOIoYFOYtgJKxR/tVZ 9mMcFMiudkbi4Mn2Lfn3rUntywQ5mfwt8lWQrfkfV86FNRJJbkw37Zqp+QgO hd/DJFjhu2WZL9nllZ1ahVqZPZ8r9HD7qkBbhnLkwDfalz8yGKPCE1sYGAX4 pmnF3qAn2hYuiAUV1IBINmXB4WTVNDf9Gsivi6rJbybBPCJfErY8JthoNRmc tXCOSoJGK5FM5LvG4SKeDBljokrNmqs0MheemBhjYACR/QTLTHQCOLemWri4 2bRogJPwrDW3jcRUEPHmN+RAqHiMyVaAEkTp+D7OGCDG2dfQQZx+oSWpd6Q0 Hdo3TDUMWxbwBwLT8KxTDwRUDT3k8WhFvSfRDqLjQWZmIue7fK2r4aFLlL56 w46LG93rPNjiLR2gbVY8A24yOh91qysgDXvatbnLwr/jiOoOFZSj8jz4Q/Av ERU/EJAkjm60D8eY3C7MIQLfi8K8D5addmEsCOJPHJybfbqXIlHefw6IeMYA BkGYLojaB+3F4ELZKYnHGXhKOBylJNY3nOKw4iTzPJkF3mbpOIDzOaBAHWY/ oRQtQSPwjccbdLvWB0DGBUYdK31D5pjYQ0Qx1dIR9oj0hilzgf7xxTQsJJlG IxAPR0yybhhimQWkAwIqiusDCW1PwGbA39iRSVY++5l3jS8KYWzTt7nx9nOz NurwyaOjL5r3CzFqPgyg8cLs+NGQbIitehneIWtXkSpAkSoX5J50Y4+nwLdH FmEnGKdAyAnCjlzdl3aJYAoGeAO49oQ+PYH/SaKkVMklIZaQLdk8qAGniQeu CRBhdoA6dkgLkLneeIV6pdtr052BmoYzLlfg7rVwwN6U+EGdmj7BIWnVbl4c aTDH/19Qk8yb+Msp+415zMudHvNvJ7b5Nfv7bcY3v2ZH3x7jsDjlfWvB1Qz6 2XnuBj61bPpZgWAOZBze8eg5Qytk3NjBZF2Loo+ySVhBrPsl9xG+VV50XS4o EqWhuE52bMEZH5cXxKf2qJTYDxvRZ0qihpOQej2p7R2BG+zqiHWhbVst3l1k SQkgcy+rFkIu0OltuUY9BWSC7ck7g8RtBIm6rf0e5jSRk/VYfSE0GkVobSYU mie5ArZ/Q8Rfg+Jz3ixWXKUJH46MIgW+y0HASoC9yUGFYjVcDGUXbx/FrkWG 2FgXpZXwIXeq4oOr+KU9ZwvkDHodbHpJbs/IKhQlhfevIuYuWUcWvybrGDsQ BtvGjOm7k7/4MJGkbnguGKTUe2O9STbvO1xyyJGEnKW5w9lJGyCiaRU6uQWI +SBkoihuicwN5r1G7rslNwzXiEohWdYmW5VIHQQJouiO6brrLGb/sFKqm3GY V4U9izY6e//q5OqEDscHac2oV/Q3IkGUu9S4cQuuC0t0gbtBHwfkAWeuKNkY UyxCSphwevTkKVf2wZpdaZlvg7a53Gi/n65iNkbvLF82GHL7+NvsCo9NSV6w 7rsGYW9xeIGYc43xL0LoGBaxr7xuqjIHsVqaHkvzypySjjBDixOC57a3JmLt SrAgagKfnwvAkokHUXywQWA3p9mfXfYnBESHcbB0NCEuuGPaDrJDSBUVQewS ig0rVTLgC8k/TLP3JFB9TVtNZ23ir4ZTR8MFrUu6EAG/W5wVHobAG1hMvgXC nTh2QP0QjItQJclzj2kVSQspOVAP7QutJ+FAS3Qp8HTIm596KIRP159oWa/7 bgYMzgl+GJDjZ36KUCvQQfhx3qzF2saJxOzlwKlW22c9Ch36DBdxnqVU0iIK utOSJ662YX6Koug06UvY1jATN0MZVW6yKKhn2AGrDvCPrtP5jWmjvAzE2Ask GLJvlP0MBQesLGzW162ptJTsxUUHexS7prK/GH2xqDuBJcn0By5xoUprpsIg EaQQMcuoCwAERUhwd1WP5GLZFd6I/O96HKxNDVpUF0mojFiIZYdobaRQovBC BEqYTUeEJO9y18Taf3kR8sgdg54RQQjgVxDVTb39QYXviRhpBo+QRKDCd3iW JWoiODusLZkb0P9l04qfyJG0DUl/67BCXwkF480NnoRF2iDrIOTcbdR2aYpf YlSjwu/iGsm87LUvYMfaxlpfbIP8fg1uBRpjvQcL8kD6VyBCwD7KZ1QCeCBT YspzVLSJJmjg58YkXIr1JMCQbsmRXzNHgvSiu4gXY25wE3qlwczmMpjb/EZ1 NphjkTcnYOwxKeM3H+0Rc9qOMzDuD/vk8M+6WpxtArATMGKyPt3zFkupke/J TIQqYAacGeTy+pPzIItx9yOpIbTD8jX6UtANK2YSpirsUt+g+UYZagtWdwTx gINU0AnpUH4xmu8heCU1ugrrRIAqgbXH1uv1xFrbYcWL4OErDe6aDMH8yzWL V0HbkCjTCuWxJdYapkguSPGaRY9aToCbwG1p1W7A+4nDux8/eHqfs1Klj7Qc 8ARWR4MkKLsBHbgiW7NeV65KKp4JxKKvK5IeZN47rK4IQsiVgzu3JBo08Wl2 lHRJVBIXcu3T9JioPBckGSvSWi9jtp//FUhxUhFkpsxHcJWth6xHSfZo9mB2 PBsSzgUCuGE+UjzspNxxSNW97o5yiRlWtbACzkwhVEEZKHLPA5VZue+LqJSl voDO+akD0BhdO0wmBIx4e0sLcJSSLXnzsu35pFsclePSeVSRXb/TUmgdkee2 1KAJxlFojqgOyxR9cCP5Gp9CXJtq46TMKeLtgy7qdkqlc5oOHCvfiVUYEPO5 WudsH80imAVj8u0jR11FvIcHuuhbPDUVg0SjRs75NUChncztahsrU19LeWmJ lamSlvdqKQKwwNRf4TPACG8xXj28unp7hDsntUjdI5STNB8JUbg1aW6QEKMK XCEcQPZCjIEH5V1MxN8jNgGHn/IKlF1yw8mZDZZ29RYthJ8cDqxqsACJzqmj gkLelozN7voR9a6Udbkq/8a8N6AIBEd0pquy42jYeb14nnA4t/ihWJ2E1iHE H2NhaUDZfUBgdlrDqEqIYT0aD3QJgWwSciVyNDYzrtj79ly6GytOFNixOE5w k0SbSj6YlgoebvIKRzFSKYAqSegmfq8EDBEwQbUILirYDh3GEr2J//9SoBp0 acmSjaZrcBYJGp1jEm0I4SU1ajL2xCUu5hK2dO5Us5AEuAsyiF9d6m/DZS1R i4vvP5llr7EaQkJmv06VEt4n4Rl0dnsf9TacGvbk88WtAupKEQla55A78yHZ XmKoJNIg324XOvDpXspUlGpAJkectex6iUe4d2vEARxKmEo7bihQGrZ8CYuG /GVavLqrB4L8VwdJxM1BUut8/OyYep8+cA3gW0IsQsr58MPbE+v6pB4dP3uI z6LIvy3rm62n+bGHzx5872upHz14dozv3FHdi4NekH1xN3NfJCIV/z6YHVb+ cnlPtmoslbkzsxGmUg+O6Rw3m2/gv80Cq1DKABpIRczQmzl2ngw3ginqHVxh 8aV3Opy+Kho6hQRaGq0ICW5xyYIYbUbObv+yPcTNriapFoVpqbgjjcuHSADW /N5k387AqEDIX0pbg3KbYtgXE0QO/x3Hzn6fLV25hat4ckOwDldR9QshO7Ho xugLSTFJ+EaKKpgZHObspleOvjYhKGsh77hSqwtYSnRguczOHUc8P0Z3ThCQ gxmci0ViiNBx5XqoFiaUdmCwOcO17ZgdULTKHSX7Dxq4jey73uHjRyYksase pmbFGlb3DVrOA3iJZ449qsj95IXi/tqBRxYgTrVNRRdth5d89RbH80EFkWMg R+47dNSW6IseL9vkqPZUzZwRx3y6F/qP8GSj3J6E3C04cRvqfbKJJO/u4nJm Fy9DSDv9GELVc3RGECAK+bYdZaWiBby9oApx3ZZc3OhBHI+kRFCOYP6u3HBX cwYcD420t8MyO/RNDm+4q2BnJyUYAsmroIIkYknCbAe18BKHaztsFo2LjjzO O9+4jsfYSp7JyoM1O3x1doEVNS+SkjAIWMh1Ym1I8ZomVowiEYugOLfX2bih juOnAKFyKxzuTg2UupwYvyAFMuTUe/AX3yp2UYOLBBUXCQbENYz+oaZmV1qz Zkc8KfjalSYKqPRIs+JECOLy51EO2dVCO4267ucQSZCGEBeQ0LKopxPCk1Au 49s22+2xFI+VSds8Q+2hIydkCOMi40H30Hd2NFEUdV4SC+JBkKaa+5MiG+GU FJmPtQZXlqDrL5BCDpI2rvuipGpuUc3b1QjCcsP6XVdBkCgYUQ1RsYz62Z+9 qwLJm9XPPsPHAaMrU/H1YEMcIH43ISivRvxSpm3KN1GTjCMAQewpQJe0LNJS tFRS+Np3cifGdxNgyjm2f0aVxBOJHQX1CkVSyo2LcroEn4T8KSmj94nzQMfZ WMlNtIaRypvxx76+Yurr53rwFXNh9ZJU+CQZtcgL050vVN6hXrbyQVqxKvPC xncFjIVVQ+81Rh1VUIiEJA4Qw8wjhp51XI0VcPytmbAPFHXTEh84dN1V03KR Qmz1paMV+cHL+jiLzbL3i85IxHgLJrTp7Zj9VYPrKdDxnBtXKA5PkjHyDEnH F6oJM/ACqVs5pQmF87DBru29Ik0IEN2vYHw4jGNEQ2OM4sP4w8WISolKCJca kfrobQjQf46L/5AmR7HtsxIWMyayFRanbKLcSQ+jFqXOGseLdKaeXSLXXsLU QVI06XckZeHb7gZKBX1w602BpwLnxpyG3t+XIn0OtKsd7aKCOyz6yqETkbfF KjoNyUntLppmh9alUh0KtYO3xbyOtfeWBpSU8o62F7rNyJUcJ/5BVNfkSXgo JQAE86EH7rNqUWKRUtvh5cBBR+NWgtJS0ZUVEctRsePO7bMzHtqiXkpGiWEQ FdyTpK8mvgYD3Gl2I4rbMuRoaZDUGKl1U8LbDM+81PkS2QJM8J1G6NY6N3/h PomzjPLhvtrE7FB0LOg4dnvA5+3XePWUXon7J1CpDUxDbhmXOUn1WxwgBswY MWKM4vHKMsRBSPXOTa6j3gdedlJW4mRKRNItJ758ZUQKEEkeaPnLkzMOj2fZ kEyMcjiHRee4PfhfBccLp9whQsPtybrlJhD3YgrgOhJ3SR23vweIL0UAUTIf Qec6JpA6DolmCbqbuKKlmDrubR+wiZ52BPF3rPBgS1fTuYuq3JM+IBI848lE rrqbxc/u1h617iZoSYAwKW3DLSfDuhSl3st4SJ5mhIT7uNSzgPRiAd2k7Uk4 0tUuEOtQTuu613B+nZHafcH5Ue7o0o6UdFgBiHcB9bVrbWzDLRDD227c8cQ8 TyfOXiwjO8ollkVyI658p2t9TSNHmgJU99ZdOSNAatKQU2FDGx2F4jI0FMYE 8mQJKtvtewXkZi69QYCVMssVpk+kGSBAGdLoUqHxzep+Nec6rPH55EYNVqFk qd8A7StUY2pYOUVkHJ6zxB2ihMkui1yILoB9qHj8U3ackfcOL89OjzAg5HuS Hj3B24B8SyBdYcDNghHDWioLlLHxkii82kZeeuMvq3F9+4L0UauTPxF2PUdC fWPTHgzlxfqr0PkBsGDdEtWuJQZfheGohBGova/p0qJoSfJHtM2AhpNdVzcN 95xMMOgUUyl4I1gmTUPX4EB0g6IwVNgkRnWDy+CrCug1lZ4iR1NvmNkcg9HN XyjdsRpJuGt4IcSWPZ5vogp/XHU81DbgqYiTUS116UR8FR95KQS/tBifY6Eu MpC7Herh/YcI4Jxi2I5J55wClTRuCGv15cG0vHhtUstGvVeNuEjOHo+vm0Va SoyRlulQCofyoVd8vRUnJHaOxedxGrLo8iX7adPRfPene8PMO5xSjIeJlzcd 6TFgaGyy1S1J0NiRJDBV5J6GGvi4ZoCUmRvRVQwAEVu622LrHjb1rfew8fOP ntJtYHIpmyA6GH250N/V8zmeD7qDXGZXTbDPSHLooYZ5NFGmW/UBji58NZlA oRcnduIz3EDeZHnChZ2+oWXmpiCwSMoc0YxsheSDNSoXirne9qgqJNzyBKqj KvPO4eqwDKnsC2VbdH0BxFwlRUjchygtayOskl6BUtOIIfUjsT9V01JggrW5 6vI2P8f2eRvaop3hkJz3+M2OBAowyEugZnKHnE9i19tQrB7iFttZ8+h6sYk7 7si3xspnFtgp30d38ursiGKVS0m3DyIVkD+fiFfqkqgds510MgTo2OFgYwlb 7MGfInykQsFAXGkBNMHQDEPQYEnQCoE1WPuOK6+MWjfZRDE/9j4S8WukOIQb Y0Vlb12LOfOOR9TGT/cTuO6HwAjwlcs2S8DoGkDhq+7OmHpoGiU7yn0ToC53 1YswP2B0imk7qaigflW6/5RYpFyt4WvUR4E8jhqMBhClEN9hl2gFnl9e8hUN 4LOB71pjnYsvSkpPckoBN3uDCaXBKJVNweUnwCzRfRazB5RN3dGL7pmTrkQ0 mKMGetzV160u3BYVVwTEJeeURqAG/Twt+yAcaURzccoXDPTE52+dn+HDkHFY xMlVFKCI0IhOlFZsKmekjknUOU1c8EIhhl+xZFqidWMHxj/ElTtwGncbA6UP hg7XF8WQPJzQ7+usnQPauPPNh0rcPAHzYrBLff+dBmpql8CP4ptQKoNf4EWw GUo6Sam/eZEcKQ4RJhxfUx9edMsS7y1mBhLJFbDfYrN9M4hW7OL6CgOfiluU OCtXnnNVDhoWdLHQicel8aV5mtxCfhr3Gj3sELf4heHCrKngoJVcEOIqI2WU UMsDSoy34DJq/hapsHkqjrNOLny7OQh/ee2sMm+Qd4UvdkkKUQVnG5bv7uDk 4ATT6t9W/EToHYLIyU2RDScjyCjE97v5DI27Hjl+iZ9GjeOYBGEAvl42LfTB Cvo/n59RIJZAh+QpIlDt5Iryghcn03+FKL4Qn+vJ8f3HWAFyEp0TK++OIUSp TEslK2pskUtL5huFGIs7LJchR82ANT7bV3CO6xaDzuVoLZovTNjd1nHJDsJY FTBviU0Ka7g4ROIuyXl6IWfS0iN9Oh13bXeNauak7rghGtmUe6E8WOULCjkV XJni2idIhDiNb0oItZHD27/HqMTk8RTRHQcZO3t0gtEiVAw3MAKCpB1yHFyn maNvlwV31uwcqx21NrtbdLfRRym71F101wohovYfq6ceyw3PAq7CDP0N7X08 88gV7GK09+MR9bhYeAxy0HYyESUaZaC3+wbD48Fr49fEz2JU/Js2iQstuZFL iZpwXrxj/EXZYo0dporcPQdp41nbS7mAcw7b0t5gjMBuGYWvuVmPCCNqaUHI d+RlqP8n5VW1ry82nE2YRFtXjQ27u8ZQRq6hdE0TO/UQR0wYWYGaxDyDa/5x cOlY0B7Sh+zcoaQqG10u47y50NsTPJnt61q3OhsnDpynEE/aa/kXDkaUAR7w Dobw1V7KFbdFfb9RO1LjGlIcUDy67aizIRiPrVuqfepTKOg9f+8mhYmpSYiu ksCIGshPved41V10wJnNTY0pXis1V0J3iutOT85OtmO6Utf6c7jcGFszcVMM 5ZAeG4blgw5nPMVw8YSrdB67zMjd38PzTLH5NJrHuivRW3MNZwOnZWwHETtf qcM3Xfmr0tGy4HYoz+ouI0eSFAVH2/g+DHxw5a6NnZ7WhVlDWINrfst425TQ YfaE/xPcE3sQJscNfZdsYPZd6BLkcIY7yg6SGx+i3QkVDyYEvvtmjXATs/vN ArkXkUGxmPQwKqyQFcswb3gaXy+YDa4XfEyXUztqsQ1xgYAcQ8gaEv0iTEly z5SlxgiUvZ2wcGw9O8pO4Nllv2KQAhvpKfPDx4AMfl1Lq4V1Rara+htQnPDA 16vQVVhtXiAgckc5Qb15gTi1JB/cherkQ6fWD1iDAsCun0foHOjhmq+w9LcM GPbE6bcllhpvpFvw2iduPa3HplF94rUknZ/cwX3Ypca7v2tLilTQTYka3vC3 ZQg0iCmy0ly7BgG1+159FZUYM0Y6ZV+kk6BiNQeRVCUnMTUj3kCleKGHqR8D u/7YeWY4kj4yFz774ldcJdDg4RYNag/T9TT8yfkp3y9clfNWk/s4ThHlKfbr KAIKtJlgFTYQ5C+YtopvfnM9/43cdRovJdkb5xXim4xUcqMBJiTQcaOMGfkK DAuPXMDDMcQswiesGs49AtMvXNU6L0d0TtnyDeF+ehVN7x0SnJtKcfAflEfA AhzXFIgj1whuVjFYj2HhIz5OkBFT4QR0ormUEMTAvitN2nGU6d0K9ledqNo+ 0Zd7VhTSvaNp4kBRLDKgFjYX2Q18bupkL3pSfHEzNJhhpCxQ6/EYtbRc5MdK 8zdBM1QLmK3yTZQm/M4HZbCGl9JQrtc0rXE3oZA7Em/MwWEMeoTMfPjNFq+t 6e6hOy2Z8HCfevTjIrtuFWa0itoxpvR7E4QZz3spTnduThSMYd+mv/zgxqUp T19f/Yjvvj+nj/Gw6df04AyfHIGpdRfvtEZSb9vmmy2xR23XDeGm+GNFgsHW KsqcuEII+0Ia6TZZiCTCtQplO2CXMAQ12CTfee71q2TMn0wV1aCAE9fFrBbb GAxN8SBQD9TE6S9gZ9nYmr2yx9BeSnIFhiuim5FBQ4K6fS1NLl7bDaamYon6 u84D8cSrGNyrqHN1sCXG2o2vyAXrFq4ewgIElG7Xl+vEaYKl6BwGODd7sLMh nv9CnFjnVaT5V3YHkkpsHt0X6wYm54EVOwxRgQ8bkNk4mUezC5EFUbH25zJM hx1GpSWCz+BkQCbmtSjpxLolCLZS3x9hxOFmZ6+VvF1Qkb+TPzU6iJKm5moB NlL4pRmwoYp03IvskoelGMa/S9fA1hCE7f6e4Gs8RJRu/rm4JvxuEjjpUY6O ++NeiPMvG1k2VSGONG/B1SRG/kp2Bv4PvTS2LTU8T1gUcZ5fvnMyRwkmP8s2 xxwGxFkXmtMqRlQt5xV2RFccVI/eX0rtL9Tmhms9KNe3j5A88khZB/TKOSuu cNKXxCGSbaUrDBU5RQABckzVzAEPTL0dYrH4NgZOFTk8y63NNy4kv0wUyqKc 37L7jp0VsgKBt8PNRQ3FPDreyc0/ezdvPkbVV1RY/aO7vVF+nGginjtwhD8K 8PhLEOptKroc/VO5pmH8/JLLfT/d8+N+FkUS4nS6/hkf/x3/BB6ebHTxrc32 /0SFGlBRAGZuZRJ58wJh5Q6dMu+RS0Ywv7FytPRqo93o0aFnXQzLVZQG2QFP yQsldYJ6zXA0ixuAXQG63KcGzmxjteAH4LPEhReO+Rd9nTO56VqyMJZFpavx Wk5tmzqulwzHgXhXjuUGSdkp36fmsB/+HarxX5AMyTR3fjfGrF19IxiO6zJ3 P3ei0NufSoWAlBK6m2vSIm9vlzARQciWWJgkq28Vl4wMSrOi6nHy7/lQUAlJ p1+8WsrB+PLRVrJ3aeMUSSp3kkwrdGlVHCXKb3UhgX0znHSYWXTG9d9KYt55 aadFs5yG33mYLhEl5F83m6YixFEQtUbQjeuOUkwNjyCFX224MZtQh3hDV0SC N4HtFpSSjiE6bhDgsUvkGVwxuknaYYPht9Xcz+MgG1SNpnza1X9chbtcrxw8 jQtIflEOp0nueB/pxuIEvcv6hJ8wwrIpG/9IElfERNeRzDc79abUO+wTRSK4 Q8WppkAiEH99f2ob1tJ1K1G8oCCu4Bm9QhW5+MlJltF9SahdwoIwxcFryN7A NhsV9yV2lZ2Ce1hiju6nwQ86YYEerQLGhkFc5wpeYx3uBkBzJ53/cKx9jm6b xSuUSv9rCg6JsCEbTC0BWJ5qMS9WA7N1M/W/3jHnMvN7AAA=[rfced] Please review the "Inclusive Language" portion of the online Style Guide at <https://www.rfc-editor.org/styleguide/part2/#inclusive_language>, and let us know if any changes are needed. Note that our script did not flag any words in particular, but this should still be reviewed as a best practice. --> <!-- [rfced] The following terms appear to be used inconsistently in this document. Please let us know which form is preferred. designated resolver(s) / Designated Resolver(s) _dns.resolver.arpa / "_dns.resolver.arpa" / _dns.resolver.arpa. resolver.arpa / "resolver.arpa" encrypted DNS / Encrypted DNS (used more generally, i.e., other than resolvers) --> </rfc>