AS331
United States Department of Defense (DoD)
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.
- Baseline (neutral) 65
- Government allocation +8
- Trust score 73 / 100
Experimental · trust-vectors model v1.1.0 — a transparent heuristic, not a definitive verdict. How it works →
About High Performance Computing Modernization Program
The United States Department of Defense High Performance Computing Modernization Program (HPCMP) was initiated in 1992 in response to Congressional direction to modernize the Department of Defense (DoD) laboratories’ high performance computing capabilities. The HPCMP provides supercomputers, a national research network, high-end software tools, a secure environment, and computational science experts that together enable the Defense laboratories and test centers to conduct research, development, test and technology evaluation activities.
Top CIDR ranges
| CIDR | IPs | PTR Density | Organization | Country | State | City |
|---|---|---|---|---|---|---|
| 55.19.0.0/16 | 65.5K |
0.0%
|
United States Department of Defense DoD | US | — | — |
| 55.65.0.0/16 | 65.5K |
0.0%
|
United States Department of Defense DoD | US | — | — |
| 55.70.0.0/16 | 65.5K |
0.0%
|
United States Department of Defense DoD | US | — | — |
| 55.19.2.0/24 | 256 |
0.0%
|
United States Department of Defense DoD | US | — | — |
| 55.70.190.0/24 | 256 |
0.0%
|
United States Department of Defense DoD | US | — | — |
BGP Announced Prefixes
Live BGP anomalies →Prefixes AS331 actually originates in BGP, observed across our RIPE RIS collectors. This live routing view can differ from the registry allocation above.
| Prefix | Announcement samples | Last seen |
|---|---|---|
| 55.70.190.0/24 | 33,468 | 2026-07-19 13:50:16 |
| 55.19.2.0/24 | 33,455 | 2026-07-19 13:50:16 |
| 55.70.0.0/16 | 17,485 | 2026-07-19 13:50:16 |
| 55.19.0.0/16 | 17,094 | 2026-07-19 13:50:16 |
| 55.65.0.0/16 | 17,064 | 2026-07-19 13:50:16 |
| 55.70.131.0/24 | 2,147 | 2026-06-17 15:32:32 |
Frequently Asked Questions
What is AS331?
AS331 is an Autonomous System Number assigned to United States Department of Defense (DoD). 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 AS331 announce?
AS331 announces 196.6K IPv4 addresses distributed across 5 routed CIDR prefixes. The network is registered in United States.
Who operates AS331?
AS331 is operated by United States Department of Defense DoD. The organization is based in United States. You can view all IP ranges and related ASNs on the organization page.
What country is AS331 registered in?
AS331 is registered in United States. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.
