AS4
University of Southern California
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
- Academic allocation +6
- Trust score 59 / 100
Experimental · trust-vectors model v1.1.0 — a transparent heuristic, not a definitive verdict. How it works →
About University of Southern California
The University of Southern California is a private research university in Los Angeles, California, United States. Founded in 1880 by Robert M.
⚠ 7 MOAS prefixes — multiple origin ASNs detected
All MOAS anomalies →A previously stable prefix originated by AS4 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) |
|---|---|---|
| 165.140.14.0/24 | AS4, AS400215 | 2026-07-18 11:22:44 |
| 170.79.218.0/23 | AS4, AS266306 | 2026-07-18 11:22:44 |
| 165.140.12.0/24 | AS4, AS400215 | 2026-07-18 11:22:44 |
| 165.140.13.0/24 | AS4, AS400215 | 2026-07-18 11:22:44 |
| 196.13.136.0/24 | AS4, AS327753 | 2026-07-18 11:22:44 |
| 103.199.226.0/23 | AS4, AS17747 | 2026-07-17 19:22:38 |
| 103.199.227.0/24 | AS4, AS17747 | 2026-07-17 19:22:38 |
Network profile
Source: PeeringDB →Top CIDR ranges
| CIDR | IPs | PTR Density | Organization | Country | State | City |
|---|---|---|---|---|---|---|
| 128.9.128.0/17 | 32.8K |
7.2%
|
University of Southern California | US | — | — |
| 128.9.64.0/18 | 16.4K |
3.9%
|
University of Southern California | US | — | — |
| 128.9.32.0/19 | 8.2K |
3.4%
|
University of Southern California | US | Virginia | Vienna |
| 128.9.0.0/20 | 4.1K |
0.0%
|
University of Southern California | US | — | — |
| 128.9.16.0/22 | 1.0K |
12.1%
|
University of Southern California | US | California | Los Angeles |
| 128.9.28.0/22 | 1.0K |
13.5%
|
University of Southern California | US | — | — |
| 45.228.74.0/24 | 256 |
0.0%
|
University of Southern California | AR | — | — |
| 128.9.26.0/24 | 256 |
0.0%
|
University of Southern California | US | — | — |
| 198.32.16.0/24 | 256 |
0.0%
|
University of Southern California | US | — | — |
| 206.117.6.0/24 | 256 |
62.9%
|
University of Southern California | US | — | — |
| 206.117.27.0/24 | 256 |
30.9%
|
University of Southern California | US | — | — |
| 206.117.31.0/24 | 256 |
45.7%
|
University of Southern California | US | — | — |
| 206.117.37.0/24 | 256 |
2.0%
|
University of Southern California | US | — | — |
BGP Announced Prefixes
Live BGP anomalies →Prefixes AS4 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 |
|---|---|---|
| 170.79.218.0/23 | 16,096 | 2026-07-18 07:38:17 |
| 128.9.32.0/20 | 14,078 | 2026-07-18 10:52:00 |
| 128.9.31.0/24 | 8,401 | 2026-07-18 10:53:07 |
| 196.13.137.0/24 | 8,296 | 2026-06-11 11:01:08 |
| 128.9.96.0/20 | 6,953 | 2026-07-18 10:52:00 |
| 128.9.48.0/20 | 6,399 | 2026-07-18 10:52:36 |
| 206.117.31.0/24 | 6,312 | 2026-07-18 10:52:00 |
| 128.9.64.0/20 | 6,223 | 2026-07-18 10:52:00 |
| 128.9.26.0/24 | 6,178 | 2026-07-18 10:52:00 |
| 128.9.0.0/20 | 6,175 | 2026-07-18 10:52:00 |
| 128.9.176.0/20 | 6,158 | 2026-07-18 10:52:00 |
| 128.9.112.0/20 | 6,152 | 2026-07-18 10:52:00 |
| 128.9.144.0/20 | 6,142 | 2026-07-18 10:52:00 |
| 198.32.16.0/24 | 6,131 | 2026-07-18 10:52:00 |
| 128.9.128.0/20 | 6,117 | 2026-07-18 10:52:00 |
| 206.117.27.0/24 | 6,116 | 2026-07-18 10:51:58 |
| 128.9.160.0/20 | 6,095 | 2026-07-18 10:52:00 |
| 206.117.6.0/24 | 6,093 | 2026-07-18 10:51:58 |
| 128.9.80.0/20 | 6,073 | 2026-07-18 10:52:00 |
| 206.117.37.0/24 | 6,049 | 2026-07-18 10:51:58 |
| 128.9.17.0/24 | 3,708 | 2026-07-18 10:52:00 |
| 128.9.16.0/24 | 3,705 | 2026-07-18 10:52:00 |
| 128.9.28.0/23 | 3,705 | 2026-07-18 10:52:00 |
| 128.9.30.0/24 | 3,699 | 2026-07-18 10:52:00 |
| 128.9.18.0/24 | 3,671 | 2026-07-18 10:52:00 |
| 128.9.43.0/24 | 3,423 | 2026-07-18 10:52:00 |
| 128.9.44.0/24 | 3,416 | 2026-07-18 10:52:00 |
| 128.9.40.0/24 | 3,401 | 2026-07-18 10:52:00 |
| 128.9.38.0/24 | 3,393 | 2026-07-18 10:52:00 |
| 128.9.37.0/24 | 3,391 | 2026-07-18 10:52:00 |
| 128.9.35.0/24 | 3,368 | 2026-07-18 10:52:00 |
| 128.9.34.0/24 | 3,361 | 2026-07-18 10:52:00 |
| 128.9.127.0/24 | 3,351 | 2026-07-18 10:52:00 |
| 128.9.36.0/24 | 3,342 | 2026-07-18 10:52:00 |
| 128.9.122.0/24 | 3,336 | 2026-07-18 10:52:00 |
| 128.9.47.0/24 | 3,335 | 2026-07-18 10:52:00 |
| 128.9.46.0/24 | 3,333 | 2026-07-18 10:52:00 |
| 128.9.192.0/18 | 3,331 | 2026-07-18 10:52:00 |
| 128.9.123.0/24 | 3,321 | 2026-07-18 10:52:00 |
| 128.9.117.0/24 | 3,321 | 2026-07-18 10:52:00 |
| 128.9.19.0/24 | 3,320 | 2026-07-18 10:52:00 |
| 128.9.113.0/24 | 3,315 | 2026-07-18 10:52:00 |
| 45.228.74.0/24 | 2,137 | 2026-07-18 09:47:02 |
| 45.228.73.0/24 | 2,118 | 2026-07-18 09:47:02 |
| 103.195.255.0/24 | 1,724 | 2026-05-26 02:48:47 |
| 45.228.75.0/24 | 1,684 | 2026-07-18 09:47:02 |
| 103.199.226.0/23 | 1,124 | 2026-07-17 17:28:05 |
| 165.140.14.0/24 | 779 | 2026-07-18 10:52:28 |
| 165.140.12.0/24 | 778 | 2026-07-18 10:52:28 |
| 165.140.13.0/24 | 508 | 2026-07-18 10:52:42 |
Showing top 50 of 63 announced prefixes by sample volume.
Frequently Asked Questions
What is AS4?
AS4 is an Autonomous System Number assigned to University of Southern California. 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 AS4 announce?
AS4 announces 65.3K IPv4 addresses distributed across 13 routed CIDR prefixes. The network is registered in United States.
Who operates AS4?
AS4 is operated by University of Southern California. The organization is based in United States. You can view all IP ranges and related ASNs on the organization page.
What country is AS4 registered in?
AS4 is registered in United States. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.
