AS641

AS641 is a legacy autonomous system number sitting inside DNIC-ASBLK-00616-00665, a bulk block of fifty ASNs (AS616 through AS665) that ARIN registered as a single unit to the United States Department of Defense (DoD) on 1990-04-19. The registrant record points to the DoD Network Information Center's DISA-Columbus hostmaster team, and the block's underlying organization object is "United States Department of Defense (DoD)" at 3990 E. Broad Street, Columbus, OH. Unlike a commercial or research-network ASN, AS641 has no dedicated operator website, no PeeringDB listing (that lookup returns HTTP 404), and no self-published peering policy — consistent with an internal DoD numbering reserve rather than an actively marketed network. Every routing source consulted (RIPEstat, CAIDA AS Rank) agrees AS641 is currently unrouted: zero announced IPv4/IPv6 prefixes, zero RIS peer visibility across 326 v4 and 321 v6 peers, and a customer cone that contains only itself. No public abuse or hijack history was found for AS641 specifically; a 2021 DoD-space BGP announcement event that surfaces in searches belongs to the separate ASN AS8003 and should not be conflated with this entry.

Operator

United States Department of Defense (DoD), registered via the DNIC-ASBLK-00616-00665 block (registrant org USDDD) [Confirmed] — https://rdap.arin.net/registry/autnum/641

Country / RIR

US, ARIN [Confirmed] — RIPEstat abuse-contact-finder (authoritative_rir: arin)

Allocated

1990-04-19 (ARIN RDAP autnum top-level "registration" event for the covering block; NOT an IEEE date), last changed 2025-09-12 [Confirmed, corroborated by two independent angles plus ipinfo.io] — https://rdap.arin.net/registry/autnum/641, https://ipinfo.io/AS641

Org status

registration status "active" (ARIN, last changed 2025-09-12); operationally inactive/unrouted — registration maintenance and live routing use are distinct facts here [Confirmed] — https://rdap.arin.net/registry/autnum/641, https://ipinfo.io/AS641

Website / official page

Unknown — no dedicated operator page exists for this DoD-internal block; ipinfo.io's loose association with mail.mil is DoD's general email domain, not a confirmed AS641 "about" page [Unknown] — https://ipinfo.io/AS641

Contacts

abuse/NOC disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil; DISA-Columbus, 300 North James Road, Whitehall, OH 43213 [Confirmed] — https://stat.ripe.net/AS641

Security/abuse context (NEUTRAL, DATED)

no AS641-specific listing found in Spamhaus ASN-DROP, community ASN blacklists, or NANOG archives as of 2026-07-17; the well-known 2021 DoD BGP announcement event was carried by the distinct ASN AS8003, not AS641 [Likely] — https://www.spamhaus.org/resource-hub/dnsbl/the-return-of-the-asn-drop/, https://www.kentik.com/blog/the-mystery-of-as8003/

Network & routing

Network type

US federal government / military (Department of Defense); currently unrouted — no live announcements observed [Confirmed] — https://stat.ripe.net/AS641, https://api.asrank.caida.org/v2/restful/asns/641

Size / routing

0 announced IPv4 and IPv6 prefixes; 0/326 RIS peers seeing v4, 0/321 seeing v6; 0 observed neighbours [Confirmed] — https://stat.ripe.net/AS641

Peering

no PeeringDB record (peeringdb.com/asn/641 returns 404); no self-published peering policy located [Confirmed absence] — https://www.peeringdb.com/asn/641

RPKI

not assessable — no announced prefixes, so no ROAs to validate against [Confirmed] — https://stat.ripe.net/AS641

CAIDA AS rank

79459 (source ARIN); seen=false, cliqueMember=false, all asnDegree fields 0 — likely a default placeholder for an unseen ASN rather than a meaningful topological rank [Likely] — https://api.asrank.caida.org/v2/restful/asns/641

Notable usage

none found; consistent with an unused/reserved allocation inside a large 1990-era bulk DoD block [Likely] — https://bgp.he.net/AS641, https://ipinfo.io/AS641

Related ASNs

block-mates AS616–AS665 (fifty ASNs total in DNIC-ASBLK-00616-00665); AS8003 is a separate DoD-portfolio ASN and must not be conflated with AS641 [Confirmed] — https://rdap.arin.net/registry/autnum/641

Assignment class

block allocation (DNIC-ASBLK-00616-00665, AS616–AS665); no individual per-ASN allocation date exists separate from the block-level registration event [Confirmed] — https://rdap.arin.net/registry/autnum/641

Analyst note

An unclaimed AI-search summary asserted AS641 = "PENS-NET-AS" tied to the Navy Network Information Center; no primary source (ARIN RDAP, ipinfo.io, bgp.he.net) corroborated this, so it is recorded here only as flagged-and-rejected, not as fact.