Mobile carrier

AS21928 T-Mobile USA, Inc.ASN lookup: IP ranges, prefixes and network type

AS21928 is the autonomous system number (ASN) announced by T-Mobile USA, Inc.. It announces 1,748 prefixes, 13,121,024 IPv4 addresses in total. Every address inside those ranges is routed by this operator, which is what makes the number the shortest answer to who runs a given address.

AS21928 at a glance

Reference data for AS21928
OrganisationT-Mobile USA, Inc.
Autonomous systemAS21928
Network typeMobile carrier
IPv4 prefixes34
IPv6 prefixes1,714
IPv4 addresses13,121,024Summed across every announced prefix. IPv6 is not counted; the numbers are meaningless at that scale.
In known VPN ranges0 of 34 prefixes
In known datacenter ranges0 of 34 prefixes

The last two rows are a second opinion, counted against the X4BNet VPN and datacenter range lists rather than read off the operator name. A network with most of its prefixes in the VPN list is carrying anonymised traffic whatever it calls itself.

Sample prefixes

The largest ranges T-Mobile USA, Inc. announces, biggest first. These are a sample and not the full routing table: 1,748 prefixes do not fit on a page, and the ones worth showing are the ones most traffic comes from.

The largest prefixes announced by AS21928
PrefixFamilyAddresses
100.128.0.0/9IPv48,388,608
162.160.0.0/11IPv42,097,152
172.32.0.0/11IPv42,097,152
75.122.0.0/15IPv4131,072
65.76.0.0/16IPv465,536
74.60.0.0/16IPv465,536
167.20.0.0/16IPv465,536
168.73.0.0/16IPv465,536
170.206.0.0/16IPv465,536
72.250.0.0/18IPv416,384
66.94.0.0/19IPv48,192
208.54.96.0/19IPv48,192

Live check

Look up an address on AS21928

The field is prefilled with 100.128.0.1, the first address of the largest range above. Change it for one from your own logs and you get the network, the operator and the verdict for that specific address.

ASN-Daten
Beispiele

What AS21928 means for detection

Addresses on T-Mobile USA, Inc. are mobile: phones and tablets behind carrier NAT. Our engine classifies them residential, with one caveat worth knowing. Carrier NAT puts thousands of subscribers behind one address, so an IP-level block here reaches far more people than intended, and rate limits keyed on the address will punish an entire city. Geolocation is coarse for the same reason.

The verdict for a single address is never settled by the ASN alone. It is the starting point, and IP Detection adds range membership, behaviour and history on top of it before it answers.

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