AS8698 Nationwide Building Society

Nationwide Building Society (NATIONWIDE BUILDING SOCIETY) is the world's

largest building society — a UK member-owned mutual offering mortgages, savings

and current accounts. This AS carries the society's own corporate network.

What it's used for

• Internal enterprise networking: branches, contact centres, datacentres and the back-office systems of a retail bank. Around 131,000 IPv4 addresses, which is two full legacy /16s (155.131.0.0/16 and 155.192.0.0/16), deaggregated into about 109 BGP announcements.
• Both blocks are registered to Nationwide itself in the RIPE database (NBSNET / NBSNET1, GB) under the legacy maintainer — pre-RIR class-B space, later brought under RIPE administration.

Notable

• Zero rDNS is delegated anywhere in the space. For an enterprise this is normal and deliberate: nothing here is meant to be reached from the public internet, and the address count reflects a large internal estate, not a large public presence.
• Only four BGP neighbours and no downstreams — Nationwide buys transit and announces only its own network. Nothing about this AS is an ISP, hosting provider or eyeball network despite its size.
• No IPv6 is announced.

Interesting

• A large legacy /16 pair in the hands of a single UK financial mutual is a reminder of how early-1990s address policy worked: sizeable organisations got class-B blocks essentially for the asking, and many still hold them.