Autonomous system
AS13998 SWMED
Unclassified ARIN
Summary
University of Texas Southwestern Medical Center
education research infrastructure
Twelve blocks decompose one range completely, and a hospital's name is misspelled in the netname that carries it.
What it's used for
- An academic medical centre's network. 85,504 addresses across 20 IPv4 prefixes plus one IPv6 prefix, with three observed BGP neighbours.
Notable
- Eleven blocks under the netname
UTSWMEDstep down from129.112.128.0/17through/18,/19, two/21s, three/22s and two/23s. 198.215.48.0/20usesUTSW-MHFP-B1, registered to a maternal health and family planning department.198.215.96.0/20usesUTSW-DC, and198.215.176.0/20usesZLUH, registered toZale Lipshy University Hospital.198.241.16.0/20uses the netnameNETBLK-ZALE-LIPHSY.- The IPv6 announcement is
2620:0:840::/48. - Eighteen addresses were queried for reverse DNS and none returned a name.
Interesting
- The
129.112blocks tile the whole range: a/17covering the top half, then a/18and a/19and a descending series of smaller pieces filling the bottom half exactly. Announcing an aggregate as its constituent halves is what an institution does when different parts of the same range need different paths. LIPHSYtransposes two letters of the hospital name that the other netname spells correctly. Both records are live, both are authoritative for their own block, and neither corrects the other.- A single department gets its own netname and its own
/20, which is over four thousand addresses for one clinical service. Universities allocate by organisational chart rather than by headcount, and the chart is legible in the registry decades later.
This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy. Source, and how to suggest an edit.
Interconnection
Peering at a glance
Internet exchanges
No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-20, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 20 prefixes · 85.50K addresses IPv6 1 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 21 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS13998- Registry name
- SWMED
- Registrant
- University of Texas Southwestern Medical Center
- Abuse contact
- domains@utsouthwestern.edu
- Registered
- 1999-10-01
- Last changed
- 2013-01-29
- Allocation
- assigned
Routing security
RPKI and IRR
- RPKI
- 29% valid · 4 valid, 10 with no ROA
- ROAs
- 4 authorising AS13998
- ASPA
- no ASPA record
- IRR
- 100% registered · 14 of 14 announcements
- Route objects
- 16 naming AS13998
Reputation
Classification and threat
Unclassified Not in the curated lists. Most of the ~80,000 allocated ASNs are not.
Spamhaus DROP
Not on ASN-DROP The network as a whole is not listed.
No DROP prefixes None of its announced space is on the DROP prefix list.
Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 442 networks and 1,778 prefixes, as published 2026-10-20. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.
FBI IC3
No IC3 indicators Nothing from the FBI IC3 feed.
IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.
Elsewhere