AS7287 PBI-NET-BLK2

PBI-NET-BLK2 is a legacy Pacific Bell Internet autonomous system, now held

by AT&T Enterprises, LLC after the SBC/Pacific Bell/AT&T mergers. Today it

originates a large amount of AT&T subscriber address space.

What it's used for

• Announcing hundreds of prefixes — roughly 420,000 IPv4 addresses plus IPv6 — the bulk of which are registered to AT&T Mobility (107.64.0.0/10, 108.144.0.0/13, 166.192.0.0/12, 155.165.0.0/16 and friends).
• Reverse DNS on the mobile ranges resolves to mobile-…​.mycingular.net, the long-standing rDNS suffix for AT&T's wireless data network.
• A smaller share is legacy SBC/Pacific Bell DSL space: some blocks are still named as PPPoX customer IP pools in Southern California.

Notable

• Despite the Pacific Bell handle, this is not a backbone AS — that is AS7018. AS7287 is an eyeball AS: the addresses on it are handset and broadband-subscriber pools, so traffic to it terminates at end users.
• Its only upstream neighbour is AT&T's own AS7018, confirming it as an internal customer-facing AS rather than an independent network.

Interesting

• The handle is a fossil. Pacific Bell Internet was the consumer ISP arm of Pacific Bell, which SBC acquired in 1997; SBC then bought AT&T in 2005 and took its name. The AS number, registered in 1996, outlived all three brands.