Deployment and Use of the Domain Name System(DNS) in Deep Space
draft-many-tiptop-dns-00

Internet Engineering Task Force                              M. Blanchet
Internet-Draft                                                  Viagenie
Intended status: Informational                               1 July 2025
Expires: 2 January 2026

    Deployment and Use of the Domain Name System(DNS) in Deep Space
                        draft-many-tiptop-dns-00

Abstract

   Deep space communications involve long delays (e.g., Earth to Mars
   has one-way delays 4-24 minutes) and intermittent communications,
   mainly because of orbital dynamics.  This document lists operational
   methods to enable local DNS name resolving on celestial body networks
   such that there are no real-time query and response flow to the
   authoritative name servers on (Earth) Internet.

Status of This Memo

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   This Internet-Draft will expire on 2 January 2026.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Use Case and Requirements . . . . . . . . . . . . . . . . . .   3
   3.  Possible Approaches . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Pre-walk of all needed names  . . . . . . . . . . . . . .   4
     3.2.  Pre-fetch of all zones in the needed name hierarchy . . .   5
     3.3.  Special zone  . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Zone Transfer Considerations  . . . . . . . . . . . . . . . .   6
   5.  DNSSEC Considerations . . . . . . . . . . . . . . . . . . . .   6
   6.  Crusing Spacecraft Considerations . . . . . . . . . . . . . .   7
   7.  Network Operations Considerations . . . . . . . . . . . . . .   7
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     10.2.  Informative References . . . . . . . . . . . . . . . . .   8
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Deep space communications involve long delays (e.g., Earth to Mars
   has one-way delays 4-24 minutes) and intermittent communications,
   mainly because of orbital dynamics.  To illustrate a simple example
   of intermittence, communications may be between a ground station on
   Earth to an asset on a planet through the use of an orbiter around
   that planet.  That orbiter may have an overpass of 20 minutes every 2
   hours.  Therefore, continuous connectivity between the two endpoints
   cannot be assumed.  However, as discussed in
   [I-D.many-tiptop-ip-architecture], orbiters may temporarily store IP
   packets until the next communication window with the next hop
   appears.  From the standpoint of the transport or upper application
   protocols, the one-way delay and the RTT will be stable while direct
   connectivity happens, and then jump to a large value while the
   orbiter is not reachable anymore, until it becomes reachable again.
   In some cases, where the asset is on a shadow side of a planet or
   Moon and while there is no full constellation of orbiters providing
   connectivity all around, the asset and Earth ground may never or
   rarely have a uninterrupted end2end path.  [I-D.many-tiptop-usecase]
   provides more details about key characteristics of deep space
   communications and the use case of networking.

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   [I-D.many-tiptop-ip-architecture] discusses the use of the whole IP
   stack in this context.  Domain name requests and response over long
   delays generate timeouts and when there is no reachability to the DNS
   server, requests will not be answered.  Therefore, on celestial
   bodies IP networks, a local DNS infrastructure with all the needed
   names and values stored locally is needed.

   While this document uses deep space as the base use case, it may
   apply to other "mostly" isolated networks, such as IoT networks.
   Mostly isolated means that most of the time the network is isolated,
   but there are times where it is not isolated and then may receive
   zone transfers or other means to populate or update its name caches.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Use Case and Requirements

   Given all the investment in technology, protocol, services,
   infrastructure, scrutiny and governance in place, the ability to use
   the current Internet DNS Root with DNSSEC even in deep space has a
   lot of merit compared to starting another root with another trust
   chain.  In order to achive that goal, which is to keep the same DNS
   root and the current DNSSEC trust chain in deep space, domain data
   and all related keys necessary for local validation should also be
   stored locally.

   The requirements and characteristics for this document use case are:

   *  domains are under the unique DNS root[RFC2826]

   *  the DNS root is deployed under some agreed community
      requirements[RFC7720]

   *  ability to sometimes reach the celestial body network name servers
      from Earth Internet to update their data cache

   *  inability to do live DNS queries to the Internet DNS
      infrastructure from space

   *  multiple network and DNS operators may exist on the celestial body
      network, each managing their own namespace and/or caches

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3.  Possible Approaches

   This section presents various approaches that should meet the
   requirements set in the previous section.  These approaches use the
   [RFC8806] approach for root zones, but augment it for the whole
   needed name hierarchy.

   All approaches share similar naming infrastructure on the target
   celestial body network:

   *  One or more authoritative name server.

   *  One or more resolvers using the above authoritative servers (or
      additional servers) in their hints/cache file.

   *  hosts using the above resolvers.

   *  DNSSEC verifying resolvers have the root trust
      anchor[trust-anchor] in their configuration.

   "Target network" used in this document means the celestial body
   network.

3.1.  Pre-walk of all needed names

   If one assumes that all names that will be used on the target network
   are known in advance, then queries walking the tree from the root
   down to the final name of all needed names can be done on Internet
   and the responses saved in a file, together with the appropriate
   DNSSEC records (TBD: should we list those: aka RRSIG, DS, DNSKEY).
   The records should contain values that are relevant to the celestial
   body network.  For example, an IP address record such as an A or AAAA
   record should resolve to an IP address relevant and reachable on the
   target network.

   The resulting file containing all the records is uploaded to the
   authoritative name servers on the target network.

   The authoritative name servers should serve the root zone and all
   required domain tree records underneath as found above.

   If a name used on the celestial body network by the hosts or
   applications is not in the uploaded file served by the local name
   servers, then the request will timeout.

   If all needed DNSSEC material is not fully uploaded, then DNSSEC
   validation will fail.

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   A method for syncing and updating all the updated records to the
   isolated network should be put in place, at the appropriate
   frequency.  Typical DNS zone tranfer mechanism may not be suitable
   because TCP transport is likely not possible in deep space.  In this
   case, other file transfer mechanisms may be used.

   Some DNS records have values containing other names, such as the SRV
   and CNAME records.  The referenced names should also be "walked".

   This setup somewhat assumes that there is a single operator for the
   DNS authoritative infrastructure on the target network.

3.2.  Pre-fetch of all zones in the needed name hierarchy

   If one assumes that the name hierarchy is known for all needed names
   used on the target network and if the operator of the DNS
   infrastructure on the target network has access to all the zones of
   the hierarchy, then these zones are saved.  They may need to be
   modified so that the NS glue records point to the appropriate local
   authoritative name servers.  These zones are then uploaded to the
   authoritative name servers on the target network.

   The authoritative name servers should serve the root zone and all
   zones discussed above.

   This approach have less risk of missing a name since all names under
   the hierarchy are uploaded.  However, if the zones are too big
   compared to the transfer capacity to the target network, then this
   solution is not appropriate.  Moreover, it may be possible that most
   of the names in the uploaded zones will not be used, therefore it is
   a possible waste of resources (bandwidth, memory/cpu on server, ...).
   Therefore, careful consideration on the chosen hierarchy, specially
   the top-level domain, is relevant.  Given deep space relative limited
   use networks, it would make sense to dedicate some top-level domain
   or subdomain for its needs.  However, it is possible to remove all
   the non-needed record from the zones before uploading them to the
   target network DNS infrastructure, but then if some names are missing
   in this removal, the same issues from the previous approach appear.
   Moreover, DNSSEC validation will fail if records are removed from a
   signed zone.

   If all needed DNSSEC material is not fully uploaded, then DNSSEC
   validation will fail.

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   A method for syncing and updating all the updated records to the
   target network should be put in place, at the appropriate frequency.
   Typical DNS zone tranfer mechanism may not be suitable because TCP
   transport is likely not possible in deep space.  In this case, other
   file transfer mechanisms may be used.

   In the context of multiple operators on the target network, each one
   may do this process independently for its own zones, without having
   to rely on another party.

3.3.  Special zone

   Instead of fetching a whole zone containing a lot of non useful
   records, the manager of that zone creates a special version of the
   zone containing only the useful records and sign it.  It is then sent
   to the target network DNS infrastructure.  This approach is a
   combination of the previous approaches, but require careful
   management of the two versions of the zone.  In terms of deployment
   and operations, it has the same properties as the zone pre-fetch
   approach.

4.  Zone Transfer Considerations

   If DNS zone transfer is possible over the link between the Internet
   and the target network, then incremental zone transfer (aka IXFR)
   might be advised to minimize the use of the bandwidth and also
   minimize the data merge on the target DNS server.

   If DNS zone transfer is not possible or not optimal, than another
   file transfer mechanism should be used.

5.  DNSSEC Considerations

   Zones are signed at various frequencies based on the operator
   policies.  If a signature on a record has expired, then DNSSEC
   validation will fail.  Therefore, the frequency of uploading updated
   records should be higher than the frequency of the signing of the
   uploaded zones.

   Similarly, the key lifetimes, including the root zone anchor, should
   be monitored to make sure that new keys are uploaded before the old
   ones expire.

   Finally, the DNSSEC RR TTL values need to be longer than the update
   times.

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6.  Crusing Spacecraft Considerations

   This document assumes a minimal infrastructure on a celestial body
   surface and vicinty network.  As discussed in
   [I-D.many-tiptop-usecase], there are other instances of IP networks
   in deep space.  One of them is a cruising spacecraft which has non-
   continuous connectivity to Earth using a direct point-to-point link
   to Earth ground stations.  A cruising spacecraft typically have a
   local IP network to connect the various payloads and computers
   together.  Names may be used on the onboard network, either by a
   simple infrastructure as described in this document, or by other
   simpler means such as a static file distributed on all on-board
   computers.  When the spacecraft lands or connects to an
   infrastructure network such as a celestial body surface network, some
   names may need to be updated to use the local DNS infrastructure.
   The transition is not discussed in this document.

7.  Network Operations Considerations

   Even with careful management, there is some probability that some
   applications or host on the target network will query names that were
   uploaded to the local DNS infrastructure, but refer to services or IP
   addresses that are not reachable from the target network.  If the
   target network do have intermittent IP connectivity to Internet but
   the link is not appropriate for live queries, such as long delays in
   deep space, costly bandwidth or very small time window of
   reachability, then the network may try to route the packets to the
   Internet.  Therefore, a mechanisms to signal unreachability may be
   appropriate to be setup at the edge of the target network.

8.  IANA Considerations

   This memo includes no request to IANA.

9.  Security Considerations

   By expanding the use of the same Internet DNS root to space, the
   space IP network naming infrastructure is then secured at the same
   level as on Internet.

10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

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   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

10.2.  Informative References

   [RFC2826]  IAB, "IAB Technical Comment on the Unique DNS Root",
              RFC 2826, DOI 10.17487/RFC2826, May 2000,
              <https://www.rfc-editor.org/info/rfc2826>.

   [RFC7720]  Blanchet, M. and L. Liman, "DNS Root Name Service Protocol
              and Deployment Requirements", BCP 40, RFC 7720,
              DOI 10.17487/RFC7720, December 2015,
              <https://www.rfc-editor.org/info/rfc7720>.

   [RFC8806]  Kumari, W. and P. Hoffman, "Running a Root Server Local to
              a Resolver", RFC 8806, DOI 10.17487/RFC8806, June 2020,
              <https://www.rfc-editor.org/info/rfc8806>.

   [trust-anchor]
              IANA, "Trust Anchors and Keys",
              <https://www.iana.org/dnssec/files>.

   [I-D.many-tiptop-usecase]
              Blanchet, M., Eddy, W., and M. Eubanks, "IP in Deep Space:
              Key Characteristics, Use Cases and Requirements", Work in
              Progress, Internet-Draft, draft-many-tiptop-usecase-03, 18
              June 2025, <https://datatracker.ietf.org/doc/html/draft-
              many-tiptop-usecase-03>.

   [I-D.many-tiptop-ip-architecture]
              Blanchet, M., Eddy, W., and T. Li, "An Architecture for IP
              in Deep Space", Work in Progress, Internet-Draft, draft-
              many-tiptop-ip-architecture-00, 1 March 2025,
              <https://datatracker.ietf.org/doc/html/draft-many-tiptop-
              ip-architecture-00>.

Acknowledgements

   The idea of the pre-walk was suggested by Warren Kumari.  The idea of
   a special zone was suggested by Mark Andrews.  All errors are
   authors'.

Author's Address

   Marc Blanchet
   Viagenie
   Canada

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   Email: marc.blanchet@viagenie.ca

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