AS13979 — ATT-IPFR

AS13979 announces 1 IPv4 prefixes covering 4 addresses and 0 IPv6 prefixes.

About this network

A carrier announcing a computer manufacturer's address space, plus a four-address block from a research network.

What it's used for

• A carrier-run enterprise network. 15,364 addresses across five IPv4 prefixes, eleven observed BGP neighbours, and no IPv6 announced.

Notable

• The AS handle is ATT-IPFR and the holder is AT&T Enterprises, LLC.
• Four blocks are 15.12.96.0/19, 15.12.80.0/20, 15.12.64.0/21 and 15.12.76.0/22, all under the netname HP-INTERNET and registered to HP Inc.
• The fifth is 137.164.35.76/30, netname CALREN, registered to CENIC.
• Routing was first seen in 2004.
• Twelve addresses were queried for reverse DNS and none returned a name.

Interesting

• A /30 is four addresses, two of them usable. Blocks that size are point-to-point links between two routers, and seeing one in a global routing table means an interconnect got announced alongside the networks it connects rather than staying inside somebody's internal routing.
• The four larger blocks fit together inside a single contiguous run of 15.12 space, so this is one allocation carved into pieces rather than four separate assignments. Whoever split it was working down from a larger block in halves and quarters.
• The registrant is a manufacturer and the announcer is a carrier, which is the ordinary shape of managed enterprise networking: the customer owns the addresses, the carrier owns the routing, and the AS number belongs to whoever operates the path rather than whoever holds the space.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.

Announced prefixes

• 137.164.35.76/30

Upstream networks

• AS30016 North American Telecommunications Corporation

Downstream networks

• AS2576 U. S. Department of Transportation
• AS8076 Department of Housing and Urban Development
• AS10616 National Oceanic and Atmospheric Administration
• AS14298 Environmental Protection Agency
• AS395700 Executive Office Of The President

Adjacent networks

• AS4473 AT&T Enterprises, LLC
• AS2576 U. S. Department of Transportation
• AS8076 Department of Housing and Urban Development
• AS4185 AT&T Enterprises, LLC
• AS10616 National Oceanic and Atmospheric Administration
• AS3423 AT&T Enterprises, LLC
• AS14298 Environmental Protection Agency
• AS395700 Executive Office Of The President
• AS30016 North American Telecommunications Corporation

Routing security

• RPKI: 0 valid, 0 invalid and 2 not-found announcements; 25 ROAs.
• ASPA: none published.
• IRR: 0% of announcements registered; 1 route objects.
• Listed in as-sets: AS-3477-ALL, AS-FRGP, AS-UOFM.