AS671

AS671 is a dormant legacy autonomous system registered to DNIC-AS-00671, "Headquarters, USAISC," under ARIN's DNIC block for U.S. military networks, and it announces zero prefixes today — it has not been visible in the global routing table since around March 2026.

The ASN was registered on 1990-04-30 per ARIN's RDAP autnum record, with the registration itself last formally changed on 2011-08-02. Its listed registrant, USAISC (U.S. Army Information Systems Command), was dismantled and redesignated U.S. Army Signal Command in September 1996; the underlying registry entry has never been updated to reflect that, and successor functions now sit under Army NETCOM.

Historically AS671 originated a single IPv4 block, 155.85.162.0/24, first observed in BGP in March 2013 and last seen in March 2026. CAIDA's topology graph does not currently observe the ASN at all (rank #79,459, customer cone limited to itself, zero measured peer, customer, or provider relationships), though bgp.he.net's routing-table archive separately records a historical adjacency to AS1733, the U.S. Department of Defense's own ASN.

No public operator website or PeeringDB listing exists for AS671, consistent with its status as an internal DoD/Army allocation rather than a commercial network.

Operator

DNIC-AS-00671 - Headquarters, USAISC (ARIN org handle HEADQU-3); legacy U.S. Army designation, the org itself was redesignated U.S. Army Signal Command in 1996 [Confirmed] — https://whois.arin.net/rest/asn/AS671.html, https://whois.arin.net/rest/org/HEADQU-3.html

Country / RIR

US, ARIN (DNIC block "1-1876", IANA 16-bit AS Numbers Registry, assigned by ARIN) [Confirmed] — https://rdap.arin.net/registry/autnum/671

Allocated

1990-04-30 (ARIN RDAP autnum top-level "registration" event); last changed 2011-08-02 (autnum top-level event — distinct from later entity-level org/contact dates, which are decoys) [Confirmed] — https://rdap.arin.net/registry/autnum/671

Website

none found — this is an internal DoD/Army network allocation, not a distinct public-facing operator [Confirmed] — https://whois.arin.net/rest/asn/AS671.html

Org status

ARIN registration remains active (org-level record last updated 2025-03-13) but still lists the pre-1996 "USAISC" name; USAISC was dismantled and redesignated U.S. Army Signal Command in September 1996, with successor functions now under Army NETCOM

[Confirmed] — https://whois.arin.net/rest/org/HEADQU-3.html, https://en.wikipedia.org/wiki/Army_Network_Enterprise_Technology_Command

IANA reference

none found [Unknown] — (blank)

Abuse / technical contact

DISA Columbus — disa.columbus.ns.mbx.arin-registrations@mail.mil, +1-844-347-2457

Security / abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-18 — not in Spamhaus ASN-DROP, abuse.ch, AbuseIPDB, or NANOG archives

Network & routing

Network type

government/military — legacy DNIC-era U.S. Army network allocation [Confirmed] — https://whois.arin.net/rest/asn/AS671.html

Size / routing

dormant — 0 IPv4/IPv6 prefixes announced; 0 of 325 v4 and 0 of 321 v6 RIS peers seeing it; CAIDA customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — https://stat.ripe.net/AS671, https://api.asrank.caida.org/v2/restful/asns/671

RPKI

not assessable — no live announcements exist to validate against ROAs [Unknown] — https://bgp.he.net/AS671

Peering policy / PeeringDB

none published; no PeeringDB entry exists (peeringdb.com/asn/671 returns 404) [Unknown] — https://www.peeringdb.com/asn/671

Historical prefix

155.85.162.0/24, first seen 2013-03-25, last seen 2026-03-01 [Confirmed] — https://bgp.he.net/AS671

Peers / upstreams

CAIDA shows zero measured relationships in its current topology; bgp.he.net separately records one historical peer/upstream, AS1733 (U.S. Department of Defense) [Likely] — https://bgp.he.net/AS671, https://api.asrank.caida.org/v2/restful/asns/671

Registered address

NETC-ANC CONUS TNOSC, Fort Huachuca, AZ 85613 [Confirmed] — https://whois.arin.net/rest/org/HEADQU-3.html

Analyst note

Encountered as a dormant legacy DoD/Army ASN with an active ARIN registration but a stale (pre-1996) org name; live routing has not been observed since ~2026-03-01/03-02.