AS3128 University of Wisconsin System

BRUWS-AS3128 - University of Wisconsin System · registered in the United States

IPv4 addresses655,61617 prefixes · 0.021% of announced IPv4

Rank in United States#143largest network in US by IPv4 space, of 18,338 · 0.05% of US

Rank worldwide#480of 79,396 networks with IPv4

IPv616 x /32 (1,048,576 x /48)1 prefixes

CountryUnited States18,679 ASNs registered there

Open AS3128 in ASN lookup Look up an IP in this network (131.210.0.1) All networks in United States

IPv4 prefixes

All 17 prefixes, in address order.

131.210.0.0/16
137.81.0.0/16
137.104.0.0/16
138.49.0.0/17
138.49.128.0/19
138.49.160.0/22
138.49.164.0/22
138.49.168.0/21
138.49.176.0/20
138.49.192.0/18
139.225.0.0/16
141.233.0.0/16
143.200.0.0/16
143.235.0.0/16
143.236.0.0/16
144.13.0.0/16
192.35.81.0/24

IPv6 prefixes

All 1 prefix.

2600:1d00::/28

Similar-sized networks in United States

ASNNameIPv4 addresses

AS22258#140 COMCAST-22258 - Comcast Cable Communications, LLC664,064

AS31822#141 CITY-UNIVERSITY-OF-NEW-YORK - City University of New York659,712

AS4193#142 WA-STATE-GOV - State of Washington655,872

AS297#144 AS297 - National Aeronautics and Space Administration649,472

AS33489#145 COMCAST-33489 - Comcast Cable Communications, LLC647,936

AS10753#146 LUMEN-LEGACY-L3-CUSTOMER-SHARED-USE - Level 3 Parent, LLC640,512

IP-to-ASN data: iptoasn.com (public domain). Snapshot downloaded 2026-11-11, refreshed daily. Ranges are what each network announces in BGP, not registry allocations. Data sources