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
- Multiple-origin (MOAS) routing anomaly −12
- Enterprise allocation +4
- Trust score 57 / 100
Experimental · trust-vectors model v1.1.0 — a transparent heuristic, not a definitive verdict. How it works →
⚠ 22 MOAS prefixes — multiple origin ASNs detected
All MOAS anomalies →A previously stable prefix originated by AS1637 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.
| Prefix | Origin ASNs | Last detected (UTC) |
|---|---|---|
| 155.28.8.0/24 | AS1516, AS1637 | 2026-07-21 01:23:07 |
| 155.28.21.0/24 | AS1516, AS1637 | 2026-07-21 01:23:07 |
| 155.28.22.0/24 | AS1516, AS1637 | 2026-07-21 01:23:07 |
| 155.28.24.0/24 | AS1516, AS1637 | 2026-07-21 01:23:07 |
| 155.28.140.0/24 | AS1516, AS1637 | 2026-07-21 01:23:07 |
| 155.28.128.0/24 | AS1516, AS1637 | 2026-07-21 01:23:07 |
| 143.74.10.0/24 | AS1516, AS1637 | 2026-07-21 00:08:07 |
| 147.242.3.0/24 | AS747, AS1637 | 2026-07-19 02:37:49 |
| 147.242.127.0/24 | AS747, AS1637 | 2026-07-19 02:37:49 |
| 147.242.21.0/24 | AS747, AS1637 | 2026-07-19 02:37:49 |
| 147.242.52.0/24 | AS747, AS1637 | 2026-07-19 02:37:49 |
| 147.242.105.0/24 | AS747, AS1637 | 2026-07-19 02:37:49 |
| 147.242.200.0/24 | AS747, AS1637 | 2026-07-19 02:37:49 |
| 147.242.236.0/24 | AS747, AS1637 | 2026-07-19 02:37:49 |
| 147.242.128.0/24 | AS747, AS1637 | 2026-07-19 02:37:49 |
Showing the 15 most recently detected of 22 MOAS prefixes. Many multi-origin prefixes on large networks are benign (anycast); see all MOAS anomalies.
Top CIDR ranges
| CIDR | IPs | PTR Density | Organization | Country | State | City |
|---|---|---|---|---|---|---|
| 143.46.0.0/16 | 65.5K |
0.0%
|
Headquarters, USAISC | US | — | — |
| 155.5.0.0/16 | 65.5K |
0.0%
|
Headquarters, USAISC | US | — | — |
| 155.6.0.0/16 | 65.5K |
0.0%
|
Headquarters, USAISC | US | — | — |
| 143.68.152.0/21 | 2.0K |
0.0%
|
Headquarters, USAISC | US | — | — |
| 6.134.24.0/22 | 1.0K |
0.0%
|
Headquarters, USAISC | US | — | — |
| 6.16.88.0/23 | 512 |
0.0%
|
Headquarters, USAISC | US | — | — |
| 147.248.24.0/24 | 256 |
0.0%
|
Headquarters, USAISC | US | — | — |
| 155.20.105.0/24 | 256 |
0.0%
|
Headquarters, USAISC | US | — | — |
| 155.20.109.0/24 | 256 |
0.0%
|
Headquarters, USAISC | US | — | — |
BGP Announced Prefixes
Live BGP anomalies →Prefixes AS1637 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 |
|---|---|---|
| 155.28.2.0/24 | 26,273 | 2026-07-01 03:49:26 |
| 155.28.21.0/24 | 17,258 | 2026-07-21 01:05:57 |
| 155.28.22.0/24 | 16,323 | 2026-07-20 10:04:40 |
| 155.28.24.0/24 | 15,900 | 2026-07-21 00:51:32 |
| 155.20.105.0/24 | 13,067 | 2026-07-21 00:35:34 |
| 155.28.131.0/24 | 12,824 | 2026-07-11 00:29:23 |
| 155.20.109.0/24 | 10,996 | 2026-07-21 00:35:34 |
| 143.46.161.0/24 | 10,739 | 2026-07-21 00:36:00 |
| 155.28.16.0/24 | 10,723 | 2026-07-09 23:05:00 |
| 143.46.25.0/24 | 10,361 | 2026-07-21 00:36:00 |
| 143.46.24.0/24 | 10,177 | 2026-07-21 00:36:00 |
| 143.46.170.0/24 | 8,178 | 2026-07-21 00:36:00 |
| 143.46.196.0/24 | 8,158 | 2026-07-21 00:36:00 |
| 155.28.15.0/24 | 8,098 | 2026-07-10 22:06:18 |
| 143.46.151.0/24 | 8,067 | 2026-07-21 00:36:00 |
| 143.77.0.0/16 | 7,854 | 2026-07-18 02:07:40 |
| 6.134.24.0/22 | 7,644 | 2026-07-21 00:36:00 |
| 155.6.22.0/24 | 7,614 | 2026-07-21 00:36:00 |
| 155.28.140.0/24 | 7,566 | 2026-07-20 20:28:38 |
| 155.28.128.0/24 | 7,076 | 2026-07-21 00:44:20 |
| 6.16.89.0/24 | 7,062 | 2026-07-21 00:36:00 |
| 155.6.0.0/16 | 7,032 | 2026-07-21 00:36:31 |
| 6.16.88.0/24 | 7,013 | 2026-07-21 00:36:00 |
| 155.28.130.0/24 | 6,974 | 2026-07-15 23:26:01 |
| 155.5.0.0/16 | 6,925 | 2026-07-21 00:36:31 |
| 155.6.98.0/24 | 6,829 | 2026-07-21 00:36:00 |
| 143.46.116.0/22 | 6,793 | 2026-07-21 00:36:00 |
| 143.46.36.0/24 | 6,785 | 2026-07-21 00:36:00 |
| 143.68.152.0/21 | 6,780 | 2026-07-21 00:36:00 |
| 143.46.49.0/24 | 6,777 | 2026-07-21 00:36:00 |
| 143.46.158.0/24 | 6,773 | 2026-07-21 00:36:00 |
| 143.46.22.0/24 | 6,768 | 2026-07-21 00:36:00 |
| 143.46.32.0/24 | 6,759 | 2026-07-21 00:36:00 |
| 143.46.150.0/24 | 6,754 | 2026-07-21 00:36:00 |
| 143.46.144.0/24 | 6,748 | 2026-07-21 00:36:00 |
| 155.6.41.0/24 | 6,740 | 2026-07-21 00:36:00 |
| 143.46.33.0/24 | 6,734 | 2026-07-21 00:36:00 |
| 143.46.140.0/24 | 6,732 | 2026-07-21 00:36:00 |
| 143.46.11.0/24 | 6,717 | 2026-07-21 00:36:00 |
| 143.46.51.0/24 | 6,710 | 2026-07-21 00:36:00 |
| 143.46.146.0/24 | 6,709 | 2026-07-21 00:36:00 |
| 143.46.20.0/24 | 6,708 | 2026-07-21 00:36:00 |
| 143.46.12.0/24 | 6,706 | 2026-07-21 00:36:00 |
| 143.46.210.0/24 | 6,706 | 2026-07-21 00:36:00 |
| 143.46.141.0/24 | 6,704 | 2026-07-21 00:36:00 |
| 143.46.21.0/24 | 6,703 | 2026-07-21 00:36:00 |
| 155.6.32.0/24 | 6,694 | 2026-07-21 00:36:00 |
| 147.248.24.0/24 | 6,694 | 2026-07-21 00:36:00 |
| 155.6.35.0/24 | 6,694 | 2026-07-21 00:36:00 |
| 155.6.55.0/24 | 6,688 | 2026-07-21 00:36:00 |
Showing top 50 of 237 announced prefixes by sample volume.
Frequently Asked Questions
What is AS1637?
AS1637 is an Autonomous System Number assigned to Headquarters, USAISC. 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 AS1637 announce?
AS1637 announces 201.0K IPv4 addresses distributed across 9 routed CIDR prefixes. The network is registered in United States.
Who operates AS1637?
AS1637 is operated by Headquarters, USAISC. The organization is based in United States. You can view all IP ranges and related ASNs on the organization page.
What country is AS1637 registered in?
AS1637 is registered in United States. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.
