USAS103
Operated by Northwestern University, US.
Summary
- // analyst note
- Active R&E network; encountered as ordinary university traffic. Legacy institutional allocation, low risk. RegDate 1987-04-09 (Confirmed ARIN); announces 28 IPv4 + 1 IPv6 prefixes (RIPEstat routing-status). CAIDA AS-rank 12917, AS-degree 10 (8 providers / 2 peers), customer cone 1 ASN; IPv4 visible to 326/326 RIS peers, IPv6 319/319. Abuse contact security@northwestern.edu.
- // security note
- NEUTRAL/DATED: no notable public abuse signal found as of 2026-06-09; clean R&E network.
About this ASN.
AS103 is a legacy spring-1987 allocation registered under ARIN to Northwestern University (OrgId NORTHW-9-Z, 2001 Sheridan Rd, Evanston, IL 60208), carrying the handle "NWU-AS." It is the campus autonomous system for Northwestern — one of the early university allocations from the original AS block, used for the university's research-and-education network. The ARIN RDAP RegDate is 1987-04-09 (autnum updated 2012-04-02). It is actively announcing 28 IPv4 prefixes (~149,504 addresses) and 1 IPv6 prefix per RIPEstat routing-status, and is broadly visible across the routing system (the IPv4 prefixes are seen by 326/326 RIS peers and the IPv6 prefix by 319/319). CAIDA ranks it at AS-rank 12917 with an AS-degree of 10 (8 providers, 2 peers) and a customer cone of a single ASN — consistent with a stub campus network rather than a transit provider. For triage this is ordinary university traffic: a clean, low-risk legacy institutional allocation, with an abuse/security contact at security@northwestern.edu and no notable public abuse signal found as of June 2026.
- Operator
- Northwestern University (ARIN OrgId NORTHW-9-Z, Evanston, IL) [Confirmed] — ARIN RDAP
- Country / RIR
- US, ARIN [Confirmed]
- Allocated
- ARIN RDAP RegDate 1987-04-09 (autnum updated 2012-04-02) [Confirmed]
- Org status
- active
Security/abuse context (NEUTRAL, DATED)
no notable public abuse signal found as of 2026-06-09; clean R&E network — ipinfo.io
Network & routing
- Network type
- research / education (university) [Confirmed]
- Size
- active; announces 28 IPv4 prefixes (~149,504 addresses) + 1 IPv6 prefix — RIPEstat routing-status (2026-06-13)
- Routing/peering
- active with multiple peers and upstreams; RPKI unknown — ipinfo.io
- Notable usage
- [current] The campus AS for Northwestern University; an early university allocation from the original AS block, used for the R&E network — northwestern.edu
- Related ASNs
- none specifically confirmed for this profile
- Analyst note
- Active R&E network; encountered as ordinary university traffic. Legacy institutional allocation, low risk.
What this network routes.
- 129.105.0.0/16
- 165.124.0.0/17
- 199.74.64.0/18
- 165.124.128.0/19
- 165.124.192.0/19
- 165.124.160.0/20
- 165.124.240.0/20
- 165.124.176.0/21
- 165.124.224.0/21
- 165.124.232.0/22
- 8.30.248.0/22
- 165.124.184.0/23
- 192.26.86.0/23
- 199.249.166.0/23
- 199.249.168.0/23
- 8.28.178.0/23
- 165.124.17.0/24
- 165.124.186.0/24
- 192.26.85.0/24
- 192.31.253.0/24
- 192.5.143.0/24
- 199.249.165.0/24
- 199.249.166.0/24
- 199.249.167.0/24
- 199.249.168.0/24
- 199.249.169.0/24
- 38.124.97.0/24
- 2620:10d:2000::/41
- 2401:eee0:140::/42
- 2401:eee0:180::/42
Who it talks to.
Neighbours observed by RouteViews at 2026-09-20, lowest ASN first. Relationships are inferences from the CAIDA AS Relationships Dataset, 2026-08-01, and establish no commercial arrangement; a dash means the inference did not resolve.
| ASN | Operator | Role |
|---|---|---|
| AS174 | Cogent Communications, LLC | upstream |
| AS2381 | — | upstream |
| AS3356 | Level 3 Parent, LLC (Lumen Technologies) | upstream |
| AS11537 | — | upstream |
| AS22335 | — | upstream |
| AS33491 | — | upstream |
| AS396450 | — | upstream |
| AS293 | Energy Sciences Network (ESnet) | peer |
| AS149433 | — | — |