subnet.im

AS4221United States Department of Defense (DoD)

United StatesRegistryARIN

As of 22nd October 2026, AS4221 (United States Department of Defense…), a network registered in the United States with ARIN, originates 2 IPv6 prefixes. It is seen behind 1 upstream network, most often AS668 (DoD High Performance Computing (Defense…). None of its announcements have a valid RPKI ROA. 100% of its routes reach at least 90% of full-feed peers.

At a glance

IPv4 prefixes

0

IPv6 prefixes

2

IPv4 addresses

0

IPv6 /64s

131k

Upstream graph

The networks AS4221 is seen behind, one and two hops out, drawn from real AS paths.

AS4221Toward the internet core
Upstream graph for AS4221: 3 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS4221United States Dep…This networkAS668DoD High Performa…AS2914NTT America, Inc.AS6939Hurricane Electri…

Networks observed one and two hops upstream of AS4221 in real AS paths. A thicker line means more vantage points saw that adjacency, so weight tracks how well attested it is — not how much traffic it carries. Adjacency is an observation; whether it is a transit purchase or a settlement-free peering is an inference, and is labelled as one wherever we show it.

Neighbouring networks

2

adjacent networks

Upstreams
150%
Peers
150%
Downstreams
00%

Networks carrying this one's traffic toward the rest of the internet.

Upstreams of AS4221
NetworkCountryRelationshipPathsVantage pts
AS668DoD High Performance Computing (Defense Research and Engineering Network)USPeer12864

Prefixes

The largest blocks AS4221 originates, widest first.

Largest prefixes originated by AS4221
PrefixAddressesVisibility
2001:480:52::/4865.5k × /6464/64
2001:480:95::/4865.5k × /6464/64

Routing health

How AS4221's own announcements validate against RPKI and how far they propagate. The same measures for the whole routing table are on the routing table in numbers.

RPKI origin validation

  • Valid0.0%0
  • Invalid0.0%0
  • No ROA100.0%2

Propagation

  • Globally propagated90% of full-feed peers or more100.0%2
  • Partially propagated40% to 90%0.0%0
  • Seen by few peersUnder 40%0.0%0

Prefix sizes

IPv6 — 2 prefixes

  • /4865.5k × /64100.0%2

Recent changes

Announcements that started or stopped since 22nd Sept 2026.

No announcement by AS4221 started or stopped in this period.

Routing data derived from RouteViews MRT archives, BGPKIT relationship inference and public registry data.