Autonomous System
AS721 · United States Department of Defense (DoD)
Overview
AS721 is announced on the Internet: RIPE RIS route collectors currently see 228 IPv4 prefixes and 2 IPv6 prefixes originated by this network. Together, its IPv4 prefixes cover 72,075,776 addresses, with overlapping prefixes counted once. In the paths the collectors record, it has no upstream neighbour (transit providers or peers) and no downstream neighbour (customers or networks it carries). AS721 was assigned by ARIN, and its registration country is United States.
Source: RIPEstat (RIPE NCC), RIS route collectors. Read on October 17, 2026 at 3:10 AM UTC. This page is refreshed at most every 12 hours.
Go further
The trace goes to 55.0.0.1, the first address of 55.0.0.0/8. An address picked inside a prefix may not answer (nothing listens there, or the network filters probes): the trace then shows the path up to the last network that replies.
Announced prefixes
IPv4 prefixes (228 prefixes)
| Prefix | Addresses |
|---|---|
| 6.16.172.0/23 | 512 |
| 6.16.174.0/24 | 256 |
| 6.64.181.0/24 | 256 |
| 55.0.0.0/8 | 16,777,216 |
| 130.22.0.0/16 | 65,536 |
| 131.4.0.0/15 | 131,072 |
| 131.16.0.0/16 | 65,536 |
| 131.32.0.0/11 | 2,097,152 |
| 131.64.0.0/13 | 524,288 |
| 131.73.0.0/16 | 65,536 |
| 131.74.0.0/15 | 131,072 |
| 131.76.0.0/14 | 262,144 |
| 131.78.3.0/24 | 256 |
| 131.78.204.0/24 | 256 |
| 131.80.0.0/14 | 262,144 |
| 131.86.0.0/15 | 131,072 |
| 131.86.0.0/16 | 65,536 |
| 131.87.0.0/16 | 65,536 |
| 132.0.0.0/10 | 4,194,304 |
| 132.80.0.0/12 | 1,048,576 |
| 132.96.0.0/11 | 2,097,152 |
| 132.128.0.0/12 | 1,048,576 |
| 134.80.0.0/16 | 65,536 |
| 134.135.0.0/16 | 65,536 |
| 134.233.0.0/16 | 65,536 |
| 134.235.0.0/16 | 65,536 |
| 136.212.0.0/14 | 262,144 |
| 136.216.0.0/14 | 262,144 |
| 136.220.0.0/15 | 131,072 |
| 137.0.0.0/13 | 524,288 |
| 137.8.0.0/14 | 262,144 |
| 137.209.0.0/16 | 65,536 |
| 137.240.0.0/14 | 262,144 |
| 138.50.0.0/16 | 65,536 |
| 138.136.0.0/13 | 524,288 |
| 138.144.0.0/12 | 1,048,576 |
| 138.160.0.0/15 | 131,072 |
| 138.162.5.0/24 | 256 |
| 138.164.0.0/14 | 262,144 |
| 138.168.0.0/14 | 262,144 |
| 138.178.0.0/15 | 131,072 |
| 138.178.0.0/16 | 65,536 |
| 138.180.0.0/16 | 65,536 |
| 139.139.0.0/16 | 65,536 |
| 139.241.0.0/16 | 65,536 |
| 139.244.1.0/24 | 256 |
| 139.244.2.0/24 | 256 |
| 139.244.4.0/24 | 256 |
| 139.244.7.0/24 | 256 |
| 140.13.73.0/24 | 256 |
| 140.21.0.0/16 | 65,536 |
| 140.35.64.0/18 | 16,384 |
| 140.152.0.0/14 | 262,144 |
| 140.153.72.0/24 | 256 |
| 140.201.0.0/16 | 65,536 |
| 141.234.0.0/15 | 131,072 |
| 143.69.0.0/16 | 65,536 |
| 143.73.0.0/16 | 65,536 |
| 143.74.0.0/16 | 65,536 |
| 143.76.0.0/16 | 65,536 |
| 143.81.0.0/16 | 65,536 |
| 143.81.0.0/17 | 32,768 |
| 143.81.103.0/24 | 256 |
| 143.81.128.0/17 | 32,768 |
| 143.83.0.0/16 | 65,536 |
| 143.84.0.0/16 | 65,536 |
| 143.85.0.0/16 | 65,536 |
| 143.85.0.0/18 | 16,384 |
| 143.85.64.0/18 | 16,384 |
| 143.85.128.0/18 | 16,384 |
| 143.85.192.0/18 | 16,384 |
| 143.86.176.0/24 | 256 |
| 143.86.204.0/23 | 512 |
| 143.138.0.0/15 | 131,072 |
| 143.140.0.0/14 | 262,144 |
| 143.144.0.0/13 | 524,288 |
| 143.156.0.0/15 | 131,072 |
| 143.212.0.0/15 | 131,072 |
| 144.100.0.0/14 | 262,144 |
| 144.104.0.0/14 | 262,144 |
| 144.104.0.0/15 | 131,072 |
| 144.109.0.0/16 | 65,536 |
| 144.182.0.0/15 | 131,072 |
| 144.251.43.0/24 | 256 |
| 146.55.22.0/23 | 512 |
| 146.55.124.0/24 | 256 |
| 146.55.127.0/24 | 256 |
| 147.130.0.0/15 | 131,072 |
| 147.216.0.0/15 | 131,072 |
| 148.48.0.0/15 | 131,072 |
| 150.192.0.0/15 | 131,072 |
| 153.23.0.0/16 | 65,536 |
| 153.24.0.0/14 | 262,144 |
| 153.24.0.0/15 | 131,072 |
| 153.26.0.0/16 | 65,536 |
| 153.29.0.0/16 | 65,536 |
| 153.29.0.0/17 | 32,768 |
| 153.29.128.0/17 | 32,768 |
| 155.7.0.0/16 | 65,536 |
| 155.8.0.0/15 | 131,072 |
Showing the first 100 of 228, in address order. Complete list on RIPEstat
IPv6 prefixes (2 prefixes)
| Prefix |
|---|
| 2608:120::/32 |
| 2608:121::/32 |
Neighbours
Upstreams (transit or peers) (0)
None seen.
Downstreams (customers) (0)
None seen.
Visibility is RIPEstat's count of how often the route collectors observed the link. It compares neighbours with each other; it is not a traffic volume.
How to read this page
An Autonomous System (AS) is a network run under one routing policy: an internet provider, a cloud, a content network, a university. Each one has a number, its ASN, assigned by a regional registry (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC), and uses BGP, the protocol networks use to tell each other where addresses are, to announce the blocks of addresses it delivers to.
A prefix such as 203.0.113.0/24 is a block of addresses: the number after the slash says how many bits are fixed, so a /24 holds 256 IPv4 addresses and a /16 holds 65,536. Networks often announce a large block and smaller pieces of it at the same time, which is why the address total counts each address once.
Neighbours come from the paths themselves. A network that appears just before this one in a path, on the collector's side, is an upstream: a transit provider or a peer. One that appears just after it is a downstream, usually a customer. Peering at an internet exchange also shows up as an upstream, so the upstream list is not a list of paid transit.
The data comes from RIPEstat, run by the RIPE NCC, which gathers the routing tables of hundreds of networks through its RIS route collectors. This page reads it when it is visited and keeps it for 12 hours at most; the BGP viewer reads it live.