AS637

AS637 is not an independently registered ASN but part of DNIC-ASBLK-00616-00665, an ARIN block registration covering AS616 through AS665, allocated on 1990-04-19 to the United States Department of Defense (DoD). This block reflects the DoD Network Information Center (DNIC) allocation scheme created for U.S. military networks in the early Internet era, administered today by DISA-Columbus at 300 North James Road, Whitehall, Ohio. Unlike a typical commercial ASN, AS637 carries no dedicated operator webpage or public peering profile: WebFetch attempts against disa.mil returned only a generic placeholder, and PeeringDB has no network object for ASN 637. Live routing data shows AS637 is actively announced, originating roughly 530 to 565 IPv4 prefixes (bgp.tools and bgp.he.net disagree slightly) covering an estimated 930,000 to 957,000 addresses, with zero IPv6 prefixes. It connects upstream to three sibling DoD autonomous systems — AS27064, AS27065, and AS27066 — and shows eight IPv4 BGP peers in third-party route collectors. RPKI posture could not be validated from the primary RIPEstat source. No public abuse signal was found for AS637 itself; it should not be confused with the unrelated 2021 NANOG-discussed episode involving AS8003's dormant DoD address space.

Operator

United States Department of Defense (DoD); registered under block DNIC-ASBLK-00616-00665, administratively handled by DISA-Columbus (DoD Network Information Center) [Confirmed] — https://rdap.arin.net/registry/autnum/637

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/637

Allocated

1990-04-19 (ARIN RDAP autnum top-level "registration" event for block DNIC-ASBLK-00616-00665, which covers AS637; entity-level dates on the contact/org records — 1993, 2007, 2009 — are decoys and were excluded); last changed 2025-09-12 [Confirmed] — https://rdap.arin.net/registry/autnum/637

Org status

active per ARIN RDAP (status: active); part of the long-standing DNIC-ASBLK-00616-00665 block held by the U.S. DoD [Confirmed] — https://rdap.arin.net/registry/autnum/637

Contacts

NOC/Technical/Abuse — MIL-HSTMST-ARIN (disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil); Administrative/Technical — REGIS10-ARIN (disa.columbus.ns.mbx.arin-registrations@mail.mil); registry address DISA-Columbus, 300 North James Road, Whitehall, OH 43213

[Confirmed] — https://rdap.arin.net/registry/autnum/637

Website / peering policy

Unknown — no verifiable dedicated operator website (disa.mil returned only an unrelated "LWC Communities" placeholder, likely bot-blocked or JS-rendered) and no PeeringDB network object exists for ASN 637 [Unknown] — https://www.disa.mil/about

IANA reference

blank — no RFC applies to an ASN registration; left blank rather than invented [Unknown]

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found for AS637 as of 2026-07-17 (Spamhaus, AbuseIPDB, NANOG archives checked); distinct from the unrelated 2021 NANOG-discussed episode where AS8003 (Global Resource Systems LLC, a separate DoD-contractor ASN) began announcing ~175M previously dormant DoD IPv4 addresses

Network & routing

Network type

U.S. government/military network (DoD-internal infrastructure), not a commercial transit or content network [Likely] — https://rdap.arin.net/registry/autnum/637, https://bgp.he.net/AS637

Size

actively announced — ~529-564 IPv4 prefixes (bgp.tools: 529; bgp.he.net: 564; sources disagree slightly) covering an estimated ~930,000-957,000 IPv4 addresses; 0 IPv6 prefixes [Confirmed zero IPv6; Likely for exact IPv4 count given source disagreement] — https://bgp.he.net/AS637, https://bgp.tools/as/637

Routing/peering

upstreams AS27064, AS27065, AS27066 (all DoD-internal, no commercial transit provider); 8 IPv4 BGP peers observed, corroborated across two independent BGP-observation sources [Confirmed] — https://bgp.he.net/AS637, https://bgp.tools/as/637

RPKI

not assessable from the primary RIPEstat source (rpki-validation call requires a --prefix parameter, none supplied); bgp.tools independently reports no RPKI validation/ROA records for AS637's routes [Likely] — https://bgp.tools/as/637

Notable usage

DoD-internal network actively announcing routes alongside sibling ASNs AS27064/AS27065/AS27066; no IPv6 deployment observed [Likely] — https://bgp.he.net/AS637

Related ASNs

AS27064, AS27065, AS27066 (DoD-internal upstreams/peers) [Confirmed] — https://bgp.tools/as/637, https://bgp.he.net/AS637

CAIDA AS rank / customer cone

AS rank 12564; customer cone = 1 ASN, 555 prefixes, 953,344 addresses (singleton cone — the ASN is its own only cone member) [Confirmed] — CAIDA ASRank canonical (this site's own tooling --type asn --id 637)