subnet.im

AS16399First Communications LLC

United StatesRegistryARIN

As of 27th September 2026, AS16399 (First Communications LLC), a network registered in the United States with ARIN, originates 21 IPv4 prefixes covering 129k addresses and 7 IPv6 prefixes. By IPv4 address space that makes it the 2,046th-largest of the 79,525 networks we see originating IPv4, and the 657th-largest of 18,428 in the United States. It is seen behind 5 upstream networks, most often AS6461 (Zayo Bandwidth) and AS3356 (Lumen (Level 3)), and in front of 2 downstream networks. None of its announcements have a valid RPKI ROA. 96% of its routes reach at least 90% of full-feed peers, and 6 prefixes are also originated by another network.

At a glance

IPv4 prefixes

21

IPv6 prefixes

7

IPv4 addresses

129k

IPv6 /64s

1.9B

Upstream graph

The networks AS16399 is seen behind, one and two hops out, drawn from real AS paths.

AS16399Toward the internet core
Upstream graph for AS16399: 12 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS16399First Communicati…This networkAS174Cogent Communicat…AS3356Lumen (Level 3)AS6461Zayo BandwidthAS40264Charter Communica…AS55089THE SEGERDAHL COR…AS1299Arelion (fka. Tel…AS151326DCConnect Communi…AS3549Lumen (fka. Globa…AS2914NTT America, Inc.AS32590Valve CorporationAS10796Charter Communica…AS20115Spectrum (Charter)

Networks observed one and two hops upstream of AS16399 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

15

adjacent networks

Upstreams
533%
Peers
853%
Downstreams
213%

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

Upstreams of AS16399
NetworkCountryRelationshipPathsVantage pts
AS6461Zayo BandwidthUSPeer84465
AS3356Lumen (Level 3)USPeer47666
AS40264Charter Communications LLCUSPeer43824
AS174Cogent Communications, LLCUSPeer37749
AS55089THE SEGERDAHL CORP.USPeer1313

Prefixes

All 28

The largest blocks AS16399 originates, widest first.

Largest prefixes originated by AS16399
PrefixAddressesVisibility
168.93.64.0/1816.4k76/81
168.93.128.0/1816.4k76/81
64.27.128.0/198.2k81/81
66.244.160.0/198.2k81/81
67.206.64.0/198.2k81/81
69.7.192.0/198.2k80/81
74.222.32.0/198.2k81/81
168.92.0.0/198.2k76/81
207.135.160.0/198.2k81/81
216.21.32.0/198.2k81/81

Routing health

How AS16399'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%28

Propagation

  • Globally propagated90% of full-feed peers or more96.4%27
  • Partially propagated40% to 90%0.0%0
  • Seen by few peersUnder 40%3.6%1

Prefix sizes

IPv4 — 21 prefixes

IPv6 — 7 prefixes

  • /36268M × /64100.0%7

Recent changes

Announcements that started or stopped since 28th Aug 2026.

No announcement by AS16399 started or stopped in this period.

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