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Autonomous System

AS391

Air Force Systems Networking

Announced IPs
283,392
CIDR prefixes
39
ASN
AS391

Reputation · trust score

A transparent 0–100 signal. Every entity starts at a neutral baseline of 65; threat-intel blocklists, exposure, reverse-DNS, routing and allocation each adjust it up or down. Higher is more trustworthy.

61/100
Moderate
How this score is built

Experimental · trust-vectors model v1.1.0 — a transparent heuristic, not a definitive verdict. How it works →

⚠ 66 MOAS prefixes — multiple origin ASNs detected

All MOAS anomalies →

A previously stable prefix originated by AS391 is now also announced by another ASN (MOAS — Multiple-Origin AS), detected from our RIPE RIS collectors. Often benign (anycast, multi-homing, or a recent transfer) — but it can signal a route leak or prefix hijack, so it's worth inspecting.

PrefixOrigin ASNsLast detected (UTC)
132.50.76.0/24 AS56, AS391 2026-07-18 11:37:44
132.50.88.0/22 AS56, AS391 2026-07-18 11:37:44
132.50.64.0/21 AS56, AS391 2026-07-18 11:37:44
132.50.72.0/21 AS56, AS391 2026-07-18 11:37:44
131.44.120.0/24 AS56, AS391 2026-07-18 11:37:44
132.37.0.0/16 AS56, AS391 2026-07-18 11:37:44
137.14.127.0/24 AS56, AS391 2026-07-18 11:37:44
132.28.38.0/23 AS56, AS391 2026-07-18 11:37:44
132.50.46.0/24 AS56, AS391 2026-07-18 11:37:44
137.14.139.0/24 AS56, AS391 2026-07-18 11:37:44
137.6.192.0/20 AS56, AS391 2026-07-18 11:37:44
131.62.160.0/21 AS56, AS391 2026-07-18 11:37:44
131.44.255.0/24 AS56, AS391 2026-07-18 11:37:44
132.28.165.0/24 AS56, AS391 2026-07-18 11:37:44
137.14.136.0/24 AS56, AS391 2026-07-18 11:37:44

Showing the 15 most recently detected of 66 MOAS prefixes. Many multi-origin prefixes on large networks are benign (anycast); see all MOAS anomalies.

Top CIDR ranges

CIDRIPsPTR DensityOrganizationCountryStateCity
128.202.0.0/16 65.5K
0.0%
Air Force Systems Networking US Colorado Colorado Springs
128.236.0.0/16 65.5K
0.0%
Air Force Systems Networking US
137.0.0.0/16 65.5K
0.0%
Air Force Systems Networking US
137.11.0.0/16 65.5K
0.0%
Air Force Systems Networking US
131.15.48.0/21 2.0K
1.9%
Air Force Systems Networking US
131.15.144.0/21 2.0K
0.0%
Air Force Systems Networking US
131.15.160.0/21 2.0K
0.0%
Air Force Systems Networking US
131.15.40.0/22 1.0K
0.0%
Air Force Systems Networking US
131.15.56.0/22 1.0K
0.3%
Air Force Systems Networking US
131.15.68.0/22 1.0K
0.9%
Air Force Systems Networking US
131.15.76.0/22 1.0K
0.0%
Air Force Systems Networking US
131.15.236.0/22 1.0K
0.0%
Air Force Systems Networking US
143.141.96.0/22 1.0K
0.0%
Air Force Systems Networking US
131.15.38.0/23 512
0.0%
Air Force Systems Networking US
131.15.44.0/23 512
0.0%
Air Force Systems Networking US
131.15.60.0/23 512
0.0%
Air Force Systems Networking US
131.15.74.0/23 512
0.2%
Air Force Systems Networking US
131.15.90.0/23 512
0.0%
Air Force Systems Networking US
131.15.98.0/23 512
0.0%
Air Force Systems Networking US
131.15.234.0/23 512
0.0%
Air Force Systems Networking US
131.15.252.0/23 512
1.2%
Air Force Systems Networking US
199.31.2.0/23 512
1.4%
Air Force Systems Networking US
131.15.46.0/24 256
0.0%
Air Force Systems Networking US
131.15.62.0/24 256
0.0%
Air Force Systems Networking US
131.15.65.0/24 256
2.0%
Air Force Systems Networking US
131.15.73.0/24 256
0.0%
Air Force Systems Networking US
131.15.80.0/24 256
0.0%
Air Force Systems Networking US
131.15.92.0/24 256
0.0%
Air Force Systems Networking US
131.15.120.0/24 256
0.0%
Air Force Systems Networking US
131.15.136.0/24 256
3.5%
Air Force Systems Networking US
131.15.208.0/24 256
0.8%
Air Force Systems Networking US
131.15.233.0/24 256
0.0%
Air Force Systems Networking US
199.251.155.0/24 256
0.0%
Air Force Systems Networking US
199.251.156.0/24 256
0.0%
Air Force Systems Networking US
204.34.211.0/24 256
3.1%
Air Force Systems Networking US
206.39.56.0/24 256
0.0%
Air Force Systems Networking US
206.39.58.0/24 256
0.0%
Air Force Systems Networking US
207.133.179.0/24 256
0.0%
Air Force Systems Networking US
207.133.189.0/24 256
0.0%
Air Force Systems Networking US

BGP Announced Prefixes

Live BGP anomalies →

Prefixes AS391 actually originates in BGP, observed across our RIPE RIS collectors. This live routing view can differ from the registry allocation above.

PrefixAnnouncement samplesLast seen
128.236.0.0/16 15,148 2026-07-18 10:51:58
204.34.211.0/24 15,116 2026-07-18 10:51:58
199.251.155.0/24 11,845 2026-07-18 10:52:00
199.251.156.0/24 11,837 2026-07-18 10:52:00
199.31.3.0/24 10,543 2026-07-18 10:52:00
128.202.0.0/16 10,504 2026-07-18 10:52:00
199.31.2.0/24 10,419 2026-07-18 10:52:00
131.15.136.0/24 10,118 2026-07-18 10:52:00
131.15.252.0/24 10,103 2026-07-18 10:52:00
131.15.208.0/24 10,072 2026-07-18 10:52:00
143.141.96.0/22 10,066 2026-07-18 10:52:00
137.0.0.0/16 10,062 2026-07-18 10:52:00
131.15.80.0/24 10,033 2026-07-18 10:52:00
131.15.98.0/23 10,025 2026-07-18 10:52:00
131.15.144.0/21 9,970 2026-07-18 10:52:00
207.133.189.0/24 9,956 2026-07-18 10:52:00
131.15.253.0/24 9,927 2026-07-18 10:52:00
206.39.58.0/24 9,917 2026-07-18 10:52:00
207.133.179.0/24 9,867 2026-07-18 10:52:00
137.11.0.0/16 9,865 2026-07-18 10:52:00
206.39.56.0/24 9,836 2026-07-18 10:52:00
131.15.239.0/24 7,146 2026-07-18 10:51:58
131.15.48.0/20 7,112 2026-07-18 10:51:58
131.15.64.0/20 7,083 2026-07-18 10:51:58
131.15.92.0/24 7,040 2026-07-18 10:51:58
131.15.40.0/21 6,991 2026-07-18 10:51:58
131.15.90.0/23 6,977 2026-07-18 10:51:58
131.15.38.0/23 6,963 2026-07-18 10:51:58
131.15.32.0/22 5,782 2026-07-17 16:29:30
131.15.16.0/20 5,779 2026-07-17 16:29:30
131.15.119.0/24 5,762 2026-07-17 16:29:30
131.15.116.0/23 5,762 2026-07-17 16:29:30
131.15.234.0/24 5,602 2026-07-18 10:51:58
131.15.160.0/21 5,577 2026-07-18 10:51:58
131.15.235.0/24 5,551 2026-07-18 10:51:58
131.15.120.0/24 5,450 2026-07-18 10:51:58
131.15.238.0/24 5,437 2026-07-18 10:51:58
131.15.237.0/24 5,434 2026-07-18 10:51:58
131.15.233.0/24 5,434 2026-07-18 10:51:58
131.15.236.0/24 5,427 2026-07-18 10:51:58
131.44.64.0/22 2,134 2026-07-17 23:19:06
131.44.32.0/21 2,131 2026-07-17 23:19:06
131.44.0.0/16 2,130 2026-07-17 23:19:06
131.105.0.0/16 2,130 2026-07-17 23:19:06
192.43.253.0/24 2,129 2026-07-17 23:19:06
131.44.4.0/24 2,128 2026-07-17 23:19:06
131.44.248.0/24 2,127 2026-07-17 23:19:06
131.44.255.0/24 2,126 2026-07-17 23:19:06
192.190.107.0/24 2,125 2026-07-17 23:19:06
131.44.249.0/24 2,124 2026-07-17 23:19:06

Showing top 50 of 338 announced prefixes by sample volume.

Frequently Asked Questions

What is AS391?

AS391 is an Autonomous System Number assigned to Air Force Systems Networking. An ASN identifies a network that controls a specific set of IP addresses and determines how traffic is routed across the internet via BGP (Border Gateway Protocol).

How many IP addresses does AS391 announce?

AS391 announces 283.4K IPv4 addresses distributed across 39 routed CIDR prefixes. The network is registered in United States.

Who operates AS391?

AS391 is operated by Air Force Systems Networking. The organization is based in United States. You can view all IP ranges and related ASNs on the organization page.

What country is AS391 registered in?

AS391 is registered in United States. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.

Last updated: 2026-07-18 11:25:31 UTC
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