AS621

AS621 is a legacy autonomous system number registered under ARIN as part of a single shared block object, DNIC-ASBLK-00616-00665 (AS616–AS665), assigned to the United States Department of Defense (DoD) and administered by the Defense Information Systems Agency (DISA) through the DoD Network Information Center (DNIC). ARIN does not maintain an individual RDAP record for AS621 alone — the RDAP query for AS621 resolves to this 50-ASN block's autnum object, whose top-level registration event dates to 1990-04-19, with a last-changed timestamp of 2025-09-12 and status Active. The registrant is listed as United States Department of Defense (DoD), handle USDDD, with an administrative address at DISA-Columbus, 300 North James Road, Whitehall, OH, and abuse contact disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil. There is no dedicated public website, PeeringDB entry, or published peering policy specific to AS621; it is government/military address space rather than a commercial network operator. Every routing data source consulted — RIPEstat, CAIDA AS Rank, and a live bgp.he.net check — agrees AS621 currently announces zero IPv4 and zero IPv6 prefixes, has zero observed BGP peers, zero upstreams, and a customer cone limited to itself. No public abuse or incident signal was found as of 2026-07-17.

Operator

United States Department of Defense (DoD), administered by DISA via the DoD Network Information Center (DNIC); ARIN registrant handle USDDD [Confirmed] — https://rdap.arin.net/registry/autnum/621

Block context

AS621 falls inside the ARIN block object DNIC-ASBLK-00616-00665 (AS616–AS665); there is no separate individual RDAP record for AS621 alone [Confirmed] — https://rdap.arin.net/registry/autnum/621, https://bgp.he.net/AS621

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/621

Allocated

1990-04-19 (ARIN autnum top-level registration event for the DNIC-ASBLK-00616-00665 block); last changed 2025-09-12 [Confirmed] — https://rdap.arin.net/registry/autnum/621 (two angles, A2 and A3, independently read the same top-level date from the RDAP events[]; entity-level dates such as 1993-05-26, 2007-01-12, and 2009-06-24 belong to POC/org sub-records and were not used)

Website / peering policy

no dedicated public website or published peering policy for AS621 specifically; no PeeringDB record exists (peeringdb.com/asn/621 returns 404) [Confirmed] — https://www.peeringdb.com/asn/621

Org status

Active per ARIN registry (block status: active) [Confirmed] — https://rdap.arin.net/registry/autnum/621

Contacts

abuse/NOC disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil (handle MIL-HSTMST-ARIN); registrations disa.columbus.ns.mbx.arin-registrations@mail.mil (handle REGIS10-ARIN); HQ 3990 E. Broad Street, Columbus, OH 43218 [Confirmed] — https://rdap.arin.net/registry/autnum/621

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-17 across Spamhaus (SBL/ASN-DROP), AbuseIPDB, abuse.ch, or NANOG/RIPE archives; consistent with an ASN that currently originates no routed address space

Network & routing

Network type

government/military (DoD internal address space), not a commercial ISP or content network in the PeeringDB sense [Likely] — https://rdap.arin.net/registry/autnum/621

Size / routing

dormant — 0 IPv4 and 0 IPv6 prefixes announced; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses; CAIDA AS rank 79459, not a clique member, not seen in CAIDA topology [Confirmed] — https://stat.ripe.net/AS621, https://asrank.caida.org/asns/621, https://bgp.he.net/AS621

RPKI

not assessable — AS621 announces no prefixes, so there are no ROAs to validate against; RIPEstat's rpki-validation was skipped for lack of a prefix argument [Confirmed] — https://stat.ripe.net/

Notable usage

none observed; part of a large, largely unrouted DoD administrative ASN block (AS616–AS665) [Confirmed] — https://bgp.he.net/AS621

Related ASNs

sibling members of the same DNIC-ASBLK-00616-00665 block, AS616 through AS665 [Confirmed] — https://rdap.arin.net/registry/autnum/621

Peers / upstreams

0 observed peers (0 of 326 v4 / 322 v6 RIS peers), 0 upstream providers per CAIDA asnDegree [Confirmed] — https://stat.ripe.net/AS621, https://asrank.caida.org/asns/621

Analyst note

AS621 is one entry in a large DoD block, currently unannounced on the public Internet; the allocation date belongs to the shared block object, not an AS621-specific event, but is a genuine first-party RIR registration date and is recorded as such.