AS645

AS645 is a legacy autonomous system number falling within DNIC-ASBLK-00616-00665, a block of consecutive ASNs (AS616 through AS665) that ARIN administers on behalf of the U.S. Department of Defense under the Defense Data Network naming convention. The registrant organization is the United States Department of Defense (DoD), ARIN org handle USDDD, with day-to-day registration and abuse handling delegated to DISA's Columbus, Ohio facility. The block's top-level RDAP registration event dates to 1990-04-19, independently corroborated by bgp.tools' free-text description of the ASN as "allocated since April 19, 1990" and matching the block's startAutnum/endAutnum range exactly — a strong first-party-plus-corroboration signal. Operationally, AS645 is dormant: every routing source checked (RIPEstat, CAIDA AS Rank, bgp.he.net, bgp.tools) agrees it announces zero IPv4 and zero IPv6 prefixes, has zero visible BGP peers or upstreams, and sits outside CAIDA's observed topology entirely (seen=false). Its CAIDA rank of 79,459 reflects that total inactivity. No PeeringDB net record exists for AS645 specifically, and no public abuse or threat-intelligence signal was found, though AbuseIPDB could not be queried directly (403 bot-protection) and Spamhaus/GreyNoise were not interactively checked. AS645 should not be conflated with the separately, actively-peered DoD ASN AS27065 (DISA), which appeared adjacent to this ASN during research but is a distinct, currently-routed number.

Operator / registrant

United States Department of Defense (DoD), ARIN org handle USDDD; NOC/abuse delegated to DISA-Columbus, 300 North James Road, Whitehall, OH 43213 [Confirmed] — https://rdap.arin.net/registry/autnum/645, https://ipinfo.io/AS645

Country / RIR

US, ARIN [Confirmed] — https://stat.ripe.net/AS645, https://rdap.arin.net/registry/autnum/645

Allocated

1990-04-19 (ARIN RDAP autnum TOP-LEVEL registration event, block-level, applies to AS645); last changed 2025-09-12 [Confirmed, two independent angles + bgp.tools corroboration] — https://rdap.arin.net/registry/autnum/645, https://bgp.tools/as/645

Org status

block DNIC-ASBLK-00616-00665 (org USDDD) is Active in ARIN RDAP; block-level last-changed 2025-09-12 [Likely, block-level not AS645-specific] — https://rdap.arin.net/registry/autnum/645

Contacts

abuse/NOC disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil; registrations disa.columbus.ns.mbx.arin-registrations@mail.mil [Confirmed] — https://stat.ripe.net/data/abuse-contact-finder/data.json?resource=645, https://rdap.arin.net/registry/autnum/645

Website

none found — no AS645-specific operator/peering-policy page on defense.gov, disa.mil, or mail.mil [Confirmed absence] — (search, no citation available for a negative result)

Security/abuse context (NEUTRAL, DATED)

no notable public abuse or threat-intel signal found as of 2026-07-17; AbuseIPDB could not be checked directly (HTTP 403 bot-protection) and Spamhaus/GreyNoise were not interactively queried, so both are [Unknown] rather than assumed clean — https://bgp.he.net/AS645, https://www.abuseipdb.com/check/asn/645

Network & routing

Network type

government/military (U.S. DoD); currently unannounced/inactive [Confirmed] — https://ipinfo.io/AS645, https://bgp.he.net/AS645

Size

0 IPv4 prefixes / 0 IPv4 addresses, 0 IPv6 prefixes; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — https://stat.ripe.net/data/routing-status/data.json?resource=645, https://api.asrank.caida.org/v2/restful/asns/645

Routing/peering

NOT announced — 0/326 RIS peers seeing v4, 0/321 seeing v6; CAIDA degree total 0 (customer 0, peer 0, provider 0); no PeeringDB net record for AS645 [Confirmed] — https://stat.ripe.net/AS645#tabId=routing, https://bgp.he.net/AS645, https://www.peeringdb.com/org/17705

RPKI

not assessable — AS645 announces no prefixes, so RIPEstat's rpki-validation was skipped (no prefix supplied) and there is no route object to validate [Confirmed] — https://stat.ripe.net/AS645

Notable usage

none identified; AS645 is inactive. Distinct from the actively-peered DoD ASN AS27065 (DISA), which must not be conflated with AS645 [Confirmed] — https://bgp.he.net/AS645, https://ipinfo.io/AS645

Related ASNs

sibling ASNs in the same DoD block AS616–AS665; separately, AS27065 (DISA) is an actively-routed DoD ASN that appeared during research and should not be confused with AS645 [Likely] — https://rdap.arin.net/registry/autnum/645

ASN / block

AS645, member of DNIC-ASBLK-00616-00665 (AS616–AS665) [Confirmed] — https://rdap.arin.net/registry/autnum/645

Third-party discrepancy note

one community source (cidr-report.org) associates a "PENS-NET-AS" name / Navy Network Information Center with this AS number, which conflicts with the first-party ARIN RDAP registrant (DoD/DNIC block) and could not be corroborated elsewhere; treated as unconfirmed and not used as the primary holder record

[Unknown] — https://www.cidr-report.org/as4637/autnums.html

Analyst note

dormant ASN within a bulk DoD block; entity-nested dates (MIL-HSTMST-ARIN 1993-05-26, REGIS10-ARIN 2009-06-24, USDDD org 2007-01-12) were correctly excluded from allocated_date as decoys — only the autnum's own top-level registration event was used.