AS12076 — MICROSOFT

AS12076 announces 1 IPv4 prefixes covering 2,048 addresses and 4 IPv6 prefixes.

About this network

An AS registered to Microsoft that announces address space belonging to the United States Patent and Trademark Office.

What it's used for

• Carrying one customer's address space. 2,048 IPv4 addresses in a single /21, four IPv6 /48s, and two observed BGP neighbours.

Notable

• The only IPv4 announcement, 151.207.40.0/21, is registered as PTONET to the United States Patent and Trademark Office, not to Microsoft.
• The IPv6 side is four separate announcements — 2608:1c1:1::/48, 4::/48, 6::/47 and 8::/48 — out of one /32, with the gaps between them left unannounced.
• One IPv4 prefix and two neighbours. Whatever this AS is for, it is not general-purpose.

Interesting

• An announcer and a registrant that disagree is one of the more informative shapes in routing data. It usually means one organisation is carrying another's space: a provider announcing a customer's blocks, which is exactly what running a government agency's infrastructure looks like from the outside.
• The netname is PTONET, from the era when the agency was simply "the PTO". The trademark half of the name arrived in the title long before it arrived in the network registration.
• Announcing four /48s with holes between them, rather than the covering block, keeps the unused space out of the routing table. It also means anyone reading the announcement can count how much of the allocation is actually in service.

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

Announced prefixes

• 151.207.40.0/21
• 2608:1c1::/47
• 2608:1c1:4::/48
• 2608:1c1:6::/47
• 2608:1c1:8::/48

Upstream networks

• AS5852 United States Department of Defense (DoD)
• AS3477 National Oceanic and Atmospheric Administration

Adjacent networks

• AS5852 United States Department of Defense (DoD)
• AS3477 National Oceanic and Atmospheric Administration