--- 1/draft-ietf-dnssd-srp-00.txt 2019-03-11 15:20:47.031004431 -0700 +++ 2/draft-ietf-dnssd-srp-01.txt 2019-03-11 15:20:48.431038714 -0700 @@ -1,113 +1,122 @@ Internet Engineering Task Force S. Cheshire Internet-Draft Apple Inc. Intended status: Informational T. Lemon -Expires: April 26, 2019 Nibbhaya Consulting - October 23, 2018 +Expires: September 12, 2019 Nibbhaya Consulting + March 11, 2019 Service Registration Protocol for DNS-Based Service Discovery - draft-ietf-dnssd-srp-00 + draft-ietf-dnssd-srp-01 Abstract The Service Registration Protocol for DNS-Based Service Discovery uses the standard DNS Update mechanism to enable DNS-Based Service - Discovery using only unicast packets. This eliminates the dependency - on Multicast DNS as the foundation layer, which greatly improves - scalability and improves performance on networks where multicast - service is not an optimal choice, particularly 802.11 (Wi-Fi) and - 802.15.4 (IoT) networks. DNS-SD Service registration uses public - keys and SIG(0) to allow services to defend their registrations - against attack. + Discovery using only unicast packets. This makes it possible to + deploy DNS Service Discovery without multicast, which greatly + improves scalability and improves performance on networks where + multicast service is not an optimal choice, particularly 802.11 + (Wi-Fi) and 802.15.4 (IoT) networks. DNS-SD Service registration + uses public keys and SIG(0) to allow services to defend their + registrations against attack. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on April 26, 2019. + This Internet-Draft will expire on September 12, 2019. Copyright Notice - Copyright (c) 2018 IETF Trust and the persons identified as the + Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents - 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Service Registration Protocol . . . . . . . . . . . . . . . . 4 2.1. What to publish . . . . . . . . . . . . . . . . . . . . . 5 2.2. Where to publish it . . . . . . . . . . . . . . . . . . . 6 2.3. How to publish it . . . . . . . . . . . . . . . . . . . . 6 2.3.1. How DNS-SD Service Registration differs from standard RFC2136 DNS Update . . . . . . . . . . . . . . . . . 7 2.3.2. Testing using standard RFC2136-compliant servers . . 7 2.3.3. How to allow services to update standard - RFC2136-compliant servers . . . . . . . . . . . . . . 7 + RFC2136-compliant servers . . . . . . . . . . . . . . 8 2.4. How to secure it . . . . . . . . . . . . . . . . . . . . 8 - 2.4.1. First-Come First-Served Naming . . . . . . . . . . . 8 - 2.4.2. SRP Server Behavior . . . . . . . . . . . . . . . . . 9 + 2.4.1. First-Come First-Served Naming . . . . . . . . . . . 9 + 2.4.2. SRP Server Behavior . . . . . . . . . . . . . . . . . 10 2.5. TTL Consistency . . . . . . . . . . . . . . . . . . . . . 12 - 2.6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . 12 - 2.6.1. Cleaning up stale data . . . . . . . . . . . . . . . 12 - 2.6.2. Sleep Proxy . . . . . . . . . . . . . . . . . . . . . 13 - 3. Security Considerations . . . . . . . . . . . . . . . . . . . 14 - 4. Privacy Considerations . . . . . . . . . . . . . . . . . . . 15 - 5. Delegation of 'services.arpa.' . . . . . . . . . . . . . . . 15 - 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 - 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 - 8.1. Normative References . . . . . . . . . . . . . . . . . . 16 - 8.2. Informative References . . . . . . . . . . . . . . . . . 17 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 + 2.6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . 13 + 2.6.1. Cleaning up stale data . . . . . . . . . . . . . . . 13 + 2.6.2. Sleep Proxy . . . . . . . . . . . . . . . . . . . . . 14 + 3. Security Considerations . . . . . . . . . . . . . . . . . . . 15 + 3.1. Source Validation . . . . . . . . . . . . . . . . . . . . 15 + 3.2. SIG(0) signature validation . . . . . . . . . . . . . . . 16 + 3.3. Required Signature Algorithm . . . . . . . . . . . . . . 16 + 4. Privacy Considerations . . . . . . . . . . . . . . . . . . . 16 + 5. Delegation of 'services.arpa.' . . . . . . . . . . . . . . . 16 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 + 6.1. Registration and Delegation of 'services.arpa' as a + Special-Use Domain Name . . . . . . . . . . . . . . . . . 17 + 6.2. 'dnssd-srp' Service Name . . . . . . . . . . . . . . . . 17 + 6.3. Anycast Address . . . . . . . . . . . . . . . . . . . . . 17 + 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 + 8.1. Normative References . . . . . . . . . . . . . . . . . . 18 + 8.2. Informative References . . . . . . . . . . . . . . . . . 19 + Appendix A. Sample BIND9 configuration for + default.services.arpa. . . . . . . . . . . . . . . . 20 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 1. Introduction DNS-Based Service Discovery [RFC6763] is a component of Zero Configuration Networking [RFC6760] [ZC] [I-D.cheshire-dnssd-roadmap]. This document describes an enhancement to DNS-Based Service Discovery [RFC6763] that allows services to automatically register their services using the DNS protocol rather than using Multicast DNS [RFC6762] (mDNS). There is already a large installed base of DNS-SD - clients that can do service discovery using the DNS protocol. This + clients that can discover services using the DNS protocol. This extension makes it much easier to take advantage of this existing functionality. This document is intended for three audiences: implementors of - software that provides services that should be advertised using DNS- - SD, implementors of DNS servers that will be used in contexts where - DNS-SD registration is needed, and administrators of networks where - DNS-SD service is required. The document is intended to provide - sufficient information to allow interoperable implementation of the - registration protocol. + software that provides services that should be advertised using + DNS-SD, implementors of DNS servers that will be used in contexts + where DNS-SD registration is needed, and administrators of networks + where DNS-SD service is required. The document is intended to + provide sufficient information to allow interoperable implementation + of the registration protocol. DNS-Based Service Discovery (DNS-SD) allows services to advertise the fact that they provide service, and to provide the information required to access that service. Clients can then discover the set of services of a particular type that are available. They can then select a service from among those that are available and obtain the information required to use it. The Service Registration Protocol for DNS-SD (SRP), described in this document, provides a reasonably secure mechanism for publishing this @@ -163,35 +172,35 @@ means appropriate to the particular use case being addressed. Full- featured devices construct the names of the SRV, TXT, and PTR records describing their service(s) as subdomains of the chosen service registration domain. For these names they then discover the zone apex of the closest enclosing DNS zone using SOA queries [I-D.ietf-dnssd-push]. Having discovered the enclosing DNS zone, they query for the "_dnssd-srp._tcp" SRV record to discover the server to which they should send DNS updates. For devices designed for Constrained-Node Networks [RFC7228] some - simplifications are used. Instead of being configured with (or + simplifications are available. Instead of being configured with (or discovering) the service registration domain, the (proposed) special- - use domain name [RFC6761] "services.arpa" is used. Instead of - learning the server to which they should send DNS updates, a fixed + use domain name [RFC6761] "default.services.arpa" is used. Instead + of learning the server to which they should send DNS updates, a fixed IPv6 anycast address is used (value TBD). Anycasts are sent using UDP unless TCP is required due to the size of the update. It is the responsibility of a Constrained-Node Network supporting SRP to provide appropriate anycast routing to deliver the DNS updates to the appropriate server. It is the responsibility of the SRP server supporting a Constrained-Node Network to handle the updates appropriately. In some network environments, updates may be accepted - directly into a local "services.arpa" zone, which has only local - visibility. In other network environments, updates for names ending - in "services.arpa" may be rewritten internally to names with broader - visibility. + directly into a local "default.services.arpa" zone, which has only + local visibility. In other network environments, updates for names + ending in "default.services.arpa" may be rewritten internally to + names with broader visibility. The reason for these different assumptions is that Constrained-Node Networks generally require special egress support, and Anycast packets captured at the Constrained-Node Network egress can be assumed to have originated locally. Low-power devices that typically use Constrained-Node Networks may have very limited battery power. The additional DNS lookups required to discover an SRP server and then communicate with it will increase the power required to advertise a service; for low-power devices, the additional flexibility this provides does not justify the additional use of @@ -247,22 +257,22 @@ 2.2. Where to publish it Multicast DNS uses a single namespace, ".local", which is valid on the local link. This convenience is not available for DNS-SD using the DNS protocol: services must exist in some specific unicast namespace. As described above, full-featured devices are responsible for knowing in what domain they should register their services. Devices made for Constrained-Node Networks register in the (proposed) special use - domain name [RFC6761] "services.arpa", and let the SRP server handle - rewriting that to a different domain if necessary. + domain name [RFC6761] "default.services.arpa", and let the SRP server + handle rewriting that to a different domain if necessary. 2.3. How to publish it It is possible to issue a DNS Update that does several things at once; this means that it's possible to do all the work of adding a PTR resource record to the PTR RRset on the Service Name if it already exists, or creating one if it doesn't, and creating or updating the Service Instance Name and Host Description in a single transaction. @@ -288,61 +298,69 @@ DNS Update DNS-SD Service Registration is based on standard RFC2136 DNS Update, with some differences: o It implements first-come first-served name allocation, protected using SIG(0) [RFC2931]. o It enforces policy about what updates are allowed. - o It optionally performs rewriting of "services.arpa" to some other - domain. + o It optionally performs rewriting of "default.services.arpa" to + some other domain. o It optionally performs automatic population of the address-to-name reverse mapping domains. o An SRP server is not required to implement general DNS Update prerequsite processing. o Simplified clients are allowed to send updates to an anycast - address, for names ending in "services.arpa" + address, for names ending in "default.services.arpa" 2.3.2. Testing using standard RFC2136-compliant servers It may be useful to set up a DNS server for testing that does not implement SRP. This can be done by configuring the server to listen - on the anycast address, or advertising it in the _dnssd-srp._tcp SRV - record. It must be configured to be authoritative for - "services.arpa", and to accept updates from hosts on local networks - for names under "services.arpa" without authentication, since such - servers will not have support for FCFS authentication Section 2.4.1. + on the anycast address, or advertising it in the + _dnssd-srp._tcp. SRV record. It must be configured to be + authoritative for "default.services.arpa", and to accept updates from + hosts on local networks for names under "default.services.arpa" + without authentication, since such servers will not have support for + FCFS authentication Section 2.4.1. A server configured in this way will be able to successfully accept and process SRP updates from services that send SRP updates. However, no constraints will be applied, and this means that the test server will accept internally inconsistent SRP updates, and will not stop two SRP updates, sent by different services, that claim the same name(s), from overwriting each other. + Since SRP updates are signed with keys, validation of the SIG(0) + algorithm used by the client can be done by manually installing the + client public key on the DNS server that will be receiving the + updates. The key can then be used to authenticate the client, and + can be used as a requirement for the update. An example + configuration for testing SRP using BIND 9 is given in Appendix A. + 2.3.3. How to allow services to update standard RFC2136-compliant servers Ordinarily SRP updates will fail when sent to an RFC 2136-compliant server that does not implement SRP because the zone being updated is - "services.arpa", and no DNS server that is not an SRP server should - normally be configured to be authoritative for "services.arpa". - Therefore, a service that sends an SRP update can tell that the - receiving server does not support SRP, but does support RFC2136, - because the RCODE will either be NOTZONE, NOTAUTH or REFUSED, or - because there is no response to the update request (when using the - anycast address) + "default.services.arpa", and no DNS server that is not an SRP server + should normally be configured to be authoritative for + "default.services.arpa". Therefore, a service that sends an SRP + update can tell that the receiving server does not support SRP, but + does support RFC2136, because the RCODE will either be NOTZONE, + NOTAUTH or REFUSED, or because there is no response to the update + request (when using the anycast address) In this case a service MAY attempt to register itself using regular RFC2136 DNS updates. To do so, it must discover the default registration zone and the DNS server designated to receive updates for that zone, as described earlier using the _dns-update._udp SRV record. It can then make the update using the port and host pointed to by the SRV record, and should use appropriate constraints to avoid overwriting competing records. Such updates are out of scope for SRP, and a service that implements SRP MUST first attempt to use SRP to register itself, and should only attempt to use RFC2136 backwards @@ -385,20 +403,26 @@ pair MUST be unique to the device. When sending DNS updates, the service includes a KEY record containing the public portion of the key in each Host Description update and each Service Description update. Each KEY record MUST contain the same public key. The update is signed using SIG(0), using the private key that corresponds to the public key in the KEY record. The lifetimes of the records in the update is set using the EDNS(0) Update Lease option [I-D.sekar-dns-ul]. + The KEY record in service description updates MAY be omitted for + brevity; if it is omitted, the SRP server MUST behave as if the same + KEY record that is given for the Host Description is also given for + each Service Description for which no KEY record is provided. + Omitted KEY records are not used when computing the SIG(0) signature. + The lifetime of the DNS-SD PTR, SRV, A, AAAA and TXT records [RFC6763] uses the LEASE field of the Update Lease option, and is typically set to two hours. This means that if a device is disconnected from the network, it does not appear in the user interfaces of devices looking for services of that type for too long. The lifetime of the KEY records is set using the KEY-LEASE field of the Update Lease Option, and should be set to a much longer time, typically 14 days. The result of this is that even though a device may be temporarily unplugged, disappearing from the network for a few @@ -432,23 +456,24 @@ o which points to a Service Instance Name o for which an update is present in the SRP update. o Service Discovery updates do not contain any deletes, and do not contain any other updates. An update is a Service Description update if, for the appropriate Service Instance Name, it contains o exactly one "Delete all RRsets from a name" update, o exactly one SRV RRset update, - o exactly one KEY RR update that adds a KEY RR that contains the + o zero or one KEY RR update that adds a KEY RR that contains the public key corresponding to the private key that was used to sign - the message, + the message (if present, the KEY MUST match the KEY RR given in + the Host Description), o one or more TXT RRset updates, o and the target of the SRV record update references a hostname for which there is a Host Description update in the SRP update. o Service Descriptions do not update any other records. An update is a Host Description update if, for the appropriate hostname, it contains o exactly one "Delete all RRsets from a name" update, o one or more A or AAAA RR update(s) @@ -475,32 +500,43 @@ that contains an update to a Service Name and an update to a Service Instance Name, where the Service Name does not reference the Service Instance Name, is not a valid SRP update message, but may be a valid RFC2136 update. Assuming that an update message has been validated with these conditions and is a valid SRP update, the server checks that the name in the Host Description update exists. If so, then the server checks to see if the KEY record on the name is the same as the KEY record in the update. The server performs the same check for the KEY records - in any Service Description update. If any existing KEY record - corresponding to a KEY record in the SRP update does not match the - KEY record in the SRP update, then the server MUST reject the SRP - update with the YXDOMAIN RCODE. + in any Service Description update. For KEY records that were + omitted, the KEY from the Host Description update is used. If any + existing KEY record corresponding to a KEY record in the SRP update + does not match the KEY record in the SRP update, then the server MUST + reject the SRP update with the YXDOMAIN RCODE. Otherwise, the server validates the SRP update using SIG(0) on the public key in the KEY record of the Host Description update. If the validation fails, the server MUST reject the SRP Update with the REFUSED RCODE. Otherwise, the SRP update is considered valid and authentic, and is processed according to the method described in - RFC2136. The status that is returned depends on the result of - processing the update. + RFC2136. + + KEY record updates omitted from Service Description update are + processed as if they had been explicitly present: every Service + Description that is updated MUST, after the update, have a KEY RR, + and it must be the same KEY RR that is present in the Host + Description to which the Service Description refers. + + The status that is returned depends on the result of processing the + update, and can be either SUCCESS or SERVFAIL: all other possible + outcomes should already have been accounted for when applying the + constraints. The server MAY add a Reverse Mapping that corresponds to the Host Description. This is not required because the Reverse Mapping serves no protocol function, but it may be useful for debugging, e.g. in annotating network packet traces or logs. The server MAY apply additional criteria when accepting updates. In some networks, it may be possible to do out-of-band registration of keys, and only accept updates from pre-registered keys. In this case, an update for a key that has not been registered should be @@ -654,20 +690,22 @@ dealing with sleep and wakeup. An SRP registration for such a device will be useful regardless of the mechanism whereby messages are delivered to the sleepy end device. For example, the message might be held in a buffer for an extended period of time by an intermediate device on a mesh network, and then delivered to the device when it wakes up. The exact details of such behaviors are out of scope for this document. 3. Security Considerations +3.1. Source Validation + SRP updates have no authorization semantics other than first-come, first-served. This means that if an attacker from outside of the administrative domain of the server knows the server's IP address, it can in principle send updates to the server that will be processed successfully. Servers should therefore be configured to reject updates from source addresses outside of the administrative domain of the server. For Anycast updates, this validation must be enforced by every router that connects the Constrained-Device Network to the unconstrained @@ -686,52 +724,85 @@ For example, a normal, authenticated RFC2136 update to any RR that was added using SRP, but that is authenticated using a different key, could be used to override a promise made by the registration protocol, by replacing all or part of the service registration information with information provided by a different client. An implementation that allows both kinds of updates should not allow updates to records added by SRP updates using different authentication and authorization credentials. +3.2. SIG(0) signature validation + + This specification does not provide a mechanism for validating + responses from DNS servers to SRP clients. In the case of + Constrained Network/Constrained Node clients, such validation isn't + practical because there's no way to establish trust. In principle, a + KEY RR could be used by a non-constrained SRP client to validate + responses from the server, but this is not required, nor do we + specify a mechanism for determining which key to use. + +3.3. Required Signature Algorithm + + For validation, SRP Servers MUST implement the ECDSAP256SHA256 + signature algorithm. SRP servers SHOULD implement the algorithms + specified in [I-D.ietf-dnsop-algorithm-update] section 3.1, in the + validation column of the table, starting with algorithm number 13. + SRP clients MUST NOT assume that any algorithm numbered lower than 13 + is available for use in validating SIG(0) signatures. + 4. Privacy Considerations 5. Delegation of 'services.arpa.' In order to be fully functional, there must be a delegation of 'services.arpa.' in the '.arpa.' zone [RFC3172]. This delegation should be set up as was done for 'home.arpa', as a result of the specification in [RFC8375]Section 7. 6. IANA Considerations +6.1. Registration and Delegation of 'services.arpa' as a Special-Use + Domain Name + IANA is requested to record the domain name 'services.arpa.' in the Special-Use Domain Names registry [SUDN]. IANA is requested, with the approval of IAB, to implement the delegation requested in Section 5. IANA is further requested to add a new entry to the "Transport- Independent Locally-Served Zones" subregistry of the the "Locally- - Served DNS Zones" registry[LSDZ]. The entry will of for + Served DNS Zones" registry[LSDZ]. The entry will be for the domain 'services.arpa.' with the description "DNS-SD Registration Protocol Special-Use Domain", listing this document as the reference. +6.2. 'dnssd-srp' Service Name + IANA is also requested to add a new entry to the Service Names and Port Numbers registry for dnssd-srp with a transport type of tcp. No port number is to be assigned. The reference should be to this document, and the Assignee and Contact information should reference the authors of this document. The Description should be as follows: Availability of DNS Service Discovery Service Registration Protocol - Service for a given domain is advertised using the "_dnssd- - srp._tcp.." SRV record gives the target host and port where - DNSSD Service Registration Service is provided for the named domain. + Service for a given domain is advertised using the + "_dnssd-srp._tcp.." SRV record gives the target host and + port where DNSSD Service Registration Service is provided for the + named domain. + +6.3. Anycast Address + + IANA is requested to allocate an IPv6 Anycast address from the IPv6 + Special-Purpose Address Registry, similar to the Port Control + Protocol anycast address, 2001:1::1. This address is referred to + within the document as TBD1, and the document should be updated to + reflect the address that was allocated. 7. Acknowledgments Thanks to Toke Hoeiland-Joergensen for a thorough technical review, to Tamara Kemper for doing a nice developmental edit, Tim Wattenberg for doing a service implementation at the Montreal Hackathon at IETF 102, Tom Pusateri for reviewing during the hackathon and afterwards, and [...] more reviewers to come, hopefully. 8. References @@ -757,20 +828,26 @@ [RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, "IPv6 Router Advertisement Options for DNS Configuration", RFC 8106, DOI 10.17487/RFC8106, March 2017, . [RFC8375] Pfister, P. and T. Lemon, "Special-Use Domain 'home.arpa.'", RFC 8375, DOI 10.17487/RFC8375, May 2018, . + [I-D.ietf-dnsop-algorithm-update] + Wouters, P. and O. Sury, "Algorithm Implementation + Requirements and Usage Guidance for DNSSEC", draft-ietf- + dnsop-algorithm-update-06 (work in progress), February + 2019. + [SUDN] "Special-Use Domain Names Registry", July 2012, . [LSDZ] "Locally-Served DNS Zones Registry", July 2011, . 8.2. Informative References @@ -825,44 +902,88 @@ DOI 10.17487/RFC7228, May 2014, . [I-D.ietf-dnssd-hybrid] Cheshire, S., "Discovery Proxy for Multicast DNS-Based Service Discovery", draft-ietf-dnssd-hybrid-08 (work in progress), March 2018. [I-D.ietf-dnssd-push] Pusateri, T. and S. Cheshire, "DNS Push Notifications", - draft-ietf-dnssd-push-15 (work in progress), September - 2018. + draft-ietf-dnssd-push-17 (work in progress), March 2019. [I-D.cheshire-dnssd-roadmap] Cheshire, S., "Service Discovery Road Map", draft- - cheshire-dnssd-roadmap-02 (work in progress), October + cheshire-dnssd-roadmap-03 (work in progress), October 2018. [I-D.cheshire-edns0-owner-option] Cheshire, S. and M. Krochmal, "EDNS0 OWNER Option", draft- cheshire-edns0-owner-option-01 (work in progress), July 2017. [ZC] Cheshire, S. and D. Steinberg, "Zero Configuration Networking: The Definitive Guide", O'Reilly Media, Inc. , ISBN 0-596-10100-7, December 2005. +Appendix A. Sample BIND9 configuration for default.services.arpa. + + zone "default.services.arpa." { + type master; + file "/etc/bind/master/service.db"; + allow-update { key demo.default.services.arpa.; }; + }; + + Zone Configuration in named.conf + +$ORIGIN . +$TTL 57600 ; 16 hours +default.services.arpa IN SOA ns3.default.services.arpa. postmaster.default.services.arpa. ( + 2951053287 ; serial + 3600 ; refresh (1 hour) + 1800 ; retry (30 minutes) + 604800 ; expire (1 week) + 3600 ; minimum (1 hour) + ) + NS ns3.default.services.arpa. + SRV 0 0 53 ns3.default.services.arpa. +$ORIGIN default.services.arpa. +$TTL 3600 ; 1 hour +_ipps._tcp PTR demo._ipps._tcp +$ORIGIN _ipps._tcp.default.services.arpa. +demo TXT "0" + SRV 0 0 9992 demo.default.services.arpa. +$ORIGIN _udp.default.services.arpa. +$TTL 3600 ; 1 hour +_dns-update PTR ns3.default.services.arpa. +$ORIGIN _tcp.default.services.arpa. +_dnssd-srp PTR ns3.default.services.arpa. +$ORIGIN default.services.arpa. +$TTL 300 ; 5 minutes +ns3 AAAA 2001:db8:0:1::1 +$TTL 3600 ; 1 hour +demo AAAA 2001:db8:0:2::1 + KEY 513 3 13 ( + qweEmaaq0FAWok5//ftuQtZgiZoiFSUsm0srWREdywQU + 9dpvtOhrdKWUuPT3uEFF5TZU6B4q1z1I662GdaUwqg== + ); alg = ECDSAP256SHA256 ; key id = 15008 + AAAA ::1 + + Example Zone file + Authors' Addresses + Stuart Cheshire Apple Inc. One Apple Park Way Cupertino, California 95014 USA Phone: +1 408 974 3207 Email: cheshire@apple.com - Ted Lemon Nibbhaya Consulting P.O. Box 958 Brattleboro, Vermont 05302 United States of America Email: mellon@fugue.com