USAS55
Operated by University of Pennsylvania, US.
Summary
- // analyst note
- A long-lived, low-risk academic ASN; encountered as the origin for University of Pennsylvania campus address space.
- // security note
- NEUTRAL/DATED: no notable public abuse signal found as of 2026-06-08; typical clean R&E network.
About this ASN.
AS55 is a legacy allocation registered under ARIN to the University of Pennsylvania, and it remains the primary autonomous system for PennNet, the university's campus network — the ARIN registry comment states verbatim that it is the "Main AS number for PennNet of the University of Pennsylvania." It has been associated with Penn since the mid-1980s, making it one of the oldest university ASNs still held by its original institution. The ARIN ASN RegDate is 1985-12-18 (updated 2021-10-14; the UNIVER-8-Z org record RegDate of 2010-01-05 is a later registry refresh). It is actively announcing, with Penn's Information Security Officer listed as the abuse contact. Exact prefix counts, AS rank, customer cone, and RPKI status were not captured this cycle and are recorded as unknown rather than guessed. For triage this is a long-lived, low-risk academic ASN, encountered as the origin for University of Pennsylvania campus address space. No notable public abuse signal was found as of June 2026.
- Operator
- University of Pennsylvania (ARIN OrgId UNIVER-8-Z, Philadelphia, PA 19104) [Confirmed] — ARIN RDAP
- Country / RIR
- US, ARIN [Confirmed]
- Allocated
- ARIN ASN RegDate 1985-12-18 (updated 2021-10-14; org RegDate 2010-01-05 is a later refresh) [Confirmed]
- Org status
- active — upenn.edu
Security/abuse context (NEUTRAL, DATED)
no notable public abuse signal found as of 2026-06-08; typical clean R&E network — bgpview.io
Network & routing
- Network type
- research / education [Confirmed]
- Size
- actively announcing; exact prefix counts not captured this cycle — Unknown — bgpview.io (2026-06)
- Routing/peering
- active; abuse contact Penn ISO; RPKI unknown — bgpview.io
- Notable usage
- primary AS for PennNet (University of Pennsylvania campus network); ARIN comment "Main AS number for PennNet of the University of Pennsylvania" — upenn.edu
- Related ASNs
- none specifically confirmed for this profile
- Analyst note
- A long-lived, low-risk academic ASN; encountered as the origin for University of Pennsylvania campus address space.
What this network routes.
- 128.91.0.0/16
- 130.91.0.0/16
- 158.130.0.0/16
- 165.123.0.0/16
- 192.84.2.0/24
- 2607:f470::/32
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 |
| AS3356 | Level 3 Parent, LLC (Lumen Technologies) | upstream |
| AS11164 | — | upstream |
| AS11537 | — | upstream |
| AS69 | University of Pennsylvania | downstream |
| AS46274 | — | downstream |