AS651

AS651 is a dormant autonomous system number sitting inside ARIN's DNIC-ASBLK-00616-00665 block, a 50-ASN range (AS616 through AS665) registered to the United States Department of Defense. Registration services for the block run through DISA-Columbus, the Defense Information Systems Agency's Ohio facility that also operates the legacy DoD Network Information Center (DoD NIC). The block's top-level ARIN RDAP registration event dates to 1990-04-19, consistent with the MILNET-era numbering blocks the DoD carved out of the early ARPANET address space; the record was last administratively changed 2025-09-12. Despite that active registry status, AS651 itself is not visible anywhere in the global routing table: every routing source consulted — RIPEstat, CAIDA AS Rank, and BGP topology data — agrees on zero announced IPv4 or IPv6 prefixes, zero observed peers, and zero upstreams. Its CAIDA AS rank of 79,459 and singleton customer cone reflect complete routing inactivity. No public abuse or security signal was found for AS651; note that it should not be confused with AS8003, a different DoD ASN behind the well-publicized 2021 dormant-address-space BGP announcement story. There is no dedicated public operator page or PeeringDB entry for AS651.

Operator

United States Department of Defense (DoD); registrant org handle USDDD, registration services under DISA-Columbus / DoD NIC [Confirmed] — https://rdap.arin.net/registry/autnum/651

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/651 (entity address 3990 E. Broad Street, Columbus, OH); RIPEstat abuse-contact-finder (authoritative_rir: arin)

Allocated

1990-04-19 (ARIN RDAP autnum TOP-LEVEL "registration" event for block DNIC-ASBLK-00616-00665, corroborated independently by ipinfo.io's "Allocation Date: April 19, 1990" and whois.ipip.net); last changed 2025-09-12 [Confirmed] — https://rdap.arin.net/registry/autnum/651, https://ipinfo.io/AS651

Org status

ARIN registry status Active (block-level record, last changed 2025-09-12) even though the ASN is not currently announcing routes — registry-active, routing-inactive [Confirmed] — https://rdap.arin.net/registry/autnum/651

Contacts

disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil (abuse/NOC/technical); HQ address 300 North James Road, Whitehall, OH 43213 (DISA-Columbus) [Confirmed] — RIPEstat abuse-contact-finder (resource=651), https://rdap.arin.net/registry/autnum/651

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-17 across abuse/threat feeds (AbuseIPDB, Spamhaus, abuse.ch) or BGP-incident sources (Kentik, BGPStream/MANRS); consistent with zero announced prefixes presenting no current abuse surface

Network & routing

Network type

U.S. federal government / military network; legacy MILNET-era block within the DoD's DNIC-ASBLK-00616-00665 range, operated under DISA's DODIN umbrella — not a commercial ISP or hosting network [Confirmed] — https://rdap.arin.net/registry/autnum/651

Size

dormant — 0 IPv4 prefixes / 0 IPv4 addresses, 0 IPv6 prefixes; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — RIPEstat routing-status + announced-prefixes (resource=651), CAIDA ASRank API (asn=651)

Routing/peering

NOT announced — 0 RIS peers seeing it out of 326 v4 / 321 v6 peers; CAIDA degree total 0 (customer 0, peer 0, provider 0); no PeeringDB record and no publicly documented peering policy [Confirmed for routing state; Unknown for peering policy] — RIPEstat routing-status (resource=651), CAIDA ASRank API

RPKI

not assessable — AS651 announces no prefixes, so there are no ROAs to validate against [Confirmed] — RIPEstat rpki-validation tool (skipped: requires a prefix parameter)

Notable usage

no notable historical usage found beyond origin in the DoD's legacy MILNET-era numbering block; do not confuse with AS8003, the separate DoD ASN behind the 2021 dormant-address-space BGP announcement/honeypot coverage

[Confirmed] — https://www.kentik.com/blog/the-mystery-of-as8003/, https://bgp.he.net/AS651

Related ASNs

part of the AS616–AS665 block (DNIC-ASBLK-00616-00665), all registered to the same DoD registrant; no distinct per-ASN allocation record separate from the block [Confirmed] — https://rdap.arin.net/registry/autnum/651

Analyst note

Dormant DoD block-member ASN with an active ARIN registration but zero live routing footprint. Two WebFetch attempts (disa.mil/about, web.archive.org for nic.mil) returned unusable content in this research pass, so no dedicated operator website is recorded — website field stays Unknown/Likely rather than fabricated.