AS521

AS521 is a legacy autonomous system number registered under ARIN to Ford Motor Company, the Dearborn, Michigan-based automaker. The ARIN RDAP autnum record's own top-level registration event dates the allocation to 1989-09-22, with a top-level last-changed event of 1996-06-10 — placing AS521 among the earliest corporate ASN assignments, from the pre-InterNIC era of ARIN-predecessor registry operations. Unlike a network-operator ASN, AS521 belongs to an end-user enterprise: Ford has no PeeringDB record for it (peeringdb.com/asn/521 returns 404) and no publicly documented peering policy. Every routing-visibility source consulted — RIPEstat, CAIDA AS Rank, and third-party BGP aggregators — agrees AS521 currently announces zero IPv4 and zero IPv6 prefixes, has zero visible BGP peers, zero upstreams, and zero downstream customers; CAIDA's customer cone for the ASN is a singleton containing only itself, with zero prefixes and zero addresses. CAIDA's AS rank sits at 79,459, near the bottom of the global ranking, consistent with total routing inactivity. ARIN still marks the underlying registry object "active" (not revoked or reclaimed), so the registration itself is live even though nothing is currently routed under it. Ford's actively-routed infrastructure runs under separate, distinct ASNs (commonly cited as AS3389 and AS28729, with AS10146 also associated with Ford in third-party lookups) rather than AS521. No public abuse, hijack, or threat-intelligence signal ties AS521 to malicious activity as of this research pass; unrelated Ford corporate data-breach news exists but is an application-layer/IT incident, not ASN-level abuse, and was deliberately excluded from the security-context field to avoid misattribution.

Operator

Ford Motor Company (ARIN org handle FORDMO; RDAP name FORD-SRL-AS) [Confirmed] — https://rdap.arin.net/registry/autnum/521

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/521

Allocated

1989-09-22 (ARIN RDAP autnum TOP-LEVEL "registration" event — a first-party RIR registry fact, not an entity-level or IEEE-style date); top-level last-changed 1996-06-10 [Confirmed, corroborated independently by A1 raw RDAP, A2, and A3] — https://rdap.arin.net/registry/autnum/521

Org status

ARIN registry status "active" (not revoked/reclaimed), but operationally dormant with no current BGP visibility — these are distinct facts (registry status vs. observed routing) and are not in conflict [Confirmed] — https://rdap.arin.net/registry/autnum/521, https://ipinfo.io/AS521

Contacts

dnsadmin@ford.com, +1-313-390-3476 (NOC/technical/abuse/administrative role, ARIN org FORDMO); org address P.O. Box 2053, RM E-1121, Dearborn, MI 48121-2053 [Confirmed] — https://rdap.arin.net/registry/autnum/521

Website

ford.com / corporate.ford.com — general corporate site; no dedicated network/IT-operations or peering page located [Likely] — https://ipinfo.io/AS521

Security/abuse context (NEUTRAL, DATED)

no notable public abuse or threat-intelligence signal found for AS521 as of 2026-07-10, checked against Spamhaus SBL/DROP/ASN-DROP, AbuseIPDB, and NANOG archives; unrelated Ford corporate data-breach news exists but is an IT/application-layer incident, not ASN-routing abuse, and is excluded here

Network & routing

Network type

end-user/enterprise ASN (automotive manufacturer's internal corporate network), not an ISP/transit provider/IXP; legacy allocation, currently dormant/unrouted [Likely] — https://rdap.arin.net/registry/autnum/521, https://ipinfo.io/AS521

Size / routing

NOT announced — 0 RIS peers seeing it (of 327 v4 / 321 v6 peers), 0 announced IPv4/IPv6 prefixes in the 2000-08-01 to 2026-07-10 query window; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — https://stat.ripe.net/AS521, https://asrank.caida.org/asns/521

Peering

no PeeringDB record exists for AS521 (404 confirmed); no publicly documented peering policy on ford.com; CAIDA asnDegree totals customer/peer/provider all 0 [Confirmed no-record, Likely absence-of-policy] — https://www.peeringdb.com/asn/521, https://asrank.caida.org/asns/521

RPKI

not assessable — AS521 announces no prefixes, so there are no live routes/ROAs to validate [Confirmed abstention, honest null] — https://stat.ripe.net/AS521

CAIDA AS rank

79,459; seen=false; cliqueMember=false [Confirmed] — https://asrank.caida.org/asns/521

Notable usage

none identified for AS521 specifically — no hosted domains or announced prefixes found; Ford's actively-routed ASNs are separate (commonly AS3389, AS28729; AS10146 also associated with Ford in third-party lookups) [Likely] — https://ipinfo.io/AS521, https://www.ipqualityscore.com/asn-details/AS3389/ford-motor-company, https://www.ipqualityscore.com/asn-details/AS10146/ford-motor-company

Data-quality note

ip2location.com lists a large aggregate IPv4/IPv6 allocation table for AS521 (16.9M+ addresses) that conflicts with the 0-prefixes-announced figure from RIPEstat/CAIDA/bgp.he.net; likely a historical/cumulative WHOIS-delegation artifact rather than current routing reality — flagged as a source conflict, not resolved as fact

[Likely conflict, stated as a range] — https://www.ip2location.com/as521, https://bgp.he.net/AS521

Analyst note

encountered as a dormant legacy ASN registered to a large automotive-industry end-user enterprise; registry status active, but zero routing footprint across every source checked and no PeeringDB presence.