AS631

AS631 is a legacy autonomous system number sitting within a single ARIN block registration, DNIC-ASBLK-00616-00665, which spans AS616 through AS665 and is held by the United States Department of Defense (DoD) and administered by the Defense Information Systems Agency (DISA) out of Columbus, Ohio. The ARIN RDAP autnum record's top-level registration event dates the block to April 19, 1990, with a last-changed timestamp of September 12, 2025 that reflects routine administrative/contact updates rather than a new allocation event. Unlike many DoD-held ASNs that carry Defense Information Systems Network (DISN) traffic, AS631 currently shows no live routing activity: RIPEstat, CAIDA AS Rank, and bgp.he.net independently agree it originates zero IPv4 and zero IPv6 prefixes, has no visible BGP peers, upstreams, or customers, and sits near the bottom of CAIDA's global ranking (rank 79,459) as an unseen, non-clique-member ASN whose customer cone is only itself. No PeeringDB record exists for AS631 (404 on both the web UI and API), and no notable public abuse or threat-intelligence signal was found for it as of July 2026, consistent with an allocated-but-dormant government block rather than an actively abused or actively routed network. RPKI posture is not assessable because there is nothing announced against which to validate a ROA.

Operator

United States Department of Defense (DoD); administered by DISA Columbus, Ohio (registrant handle USDDD) [Confirmed] — https://rdap.arin.net/registry/autnum/631

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/631

Allocated

1990-04-19 — ARIN RDAP autnum TOP-LEVEL registration event for the block DNIC-ASBLK-00616-00665 (AS616-AS665), a first-party RIR fact read from the top-level events[] array, not from any entity-nested contact date; last changed 2025-09-12 [Confirmed] — https://rdap.arin.net/registry/autnum/631

Org status

active (ARIN registry status) [Confirmed] — https://rdap.arin.net/registry/autnum/631

Website

Unknown / none specific to AS631; DISA operates disa.mil generally but no page addresses this ASN individually [Confirmed absence] — https://www.disa.mil/

Contacts

MIL-HSTMST-ARIN (noc/technical/abuse), disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil; REGIS10-ARIN (administrative/technical), disa.columbus.ns.mbx.arin-registrations@mail.mil [Confirmed] — https://rdap.arin.net/registry/autnum/631

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-17 — AS631 not present in the bad-asn-list GitHub blocklist and no relevant Spamhaus listing surfaced; consistent with an unrouted ASN

Network & routing

Network type

government/military network, part of the Defense Information Systems Network (DISN) operated by DISA [Likely] — https://rdap.arin.net/registry/autnum/631

Size / routing

unrouted — 0 IPv4 and 0 IPv6 prefixes announced; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — https://stat.ripe.net/AS631, https://asrank.caida.org/asns/631, https://bgp.he.net/AS631

Routing/peering

no upstreams, peers, or customers observed (CAIDA asnDegree all 0; RIPEstat observed_neighbours 0); no PeeringDB entry (404 on web UI and API) [Confirmed] — https://asrank.caida.org/asns/631, https://www.peeringdb.com/asn/631

RPKI

not assessable — zero announced prefixes means there is no ROA to validate against [Confirmed] — https://stat.ripe.net/AS631

Notable usage

Unknown at the AS631-specific level; the block is part of DISA's DoD DNIC allocation with no distinguishing public usage record found [Unknown]

CAIDA AS rank

79459; not a clique member; not "seen" by CAIDA's collectors [Confirmed] — https://asrank.caida.org/asns/631

Registry / block

DNIC-ASBLK-00616-00665 (range AS616-AS665); AS631 is one of many sub-allocations within this contiguous DoD block [Confirmed] — https://rdap.arin.net/registry/autnum/631

Registrant address

3990 E. Broad Street, Columbus, OH 43218 (org); NOC/technical/abuse contact address DISA-Columbus, 300 North James Road, Whitehall, OH 43213 [Confirmed] — https://rdap.arin.net/registry/autnum/631

Analyst note

NANOG-archive corroboration was attempted but is inconclusive — web search returned only false-positive term collisions (an unrelated flight number and the NANOG gene/transcription-factor); tagged Unknown rather than fabricated as a confirmed absence.