AS8791 FOEHN

FOEHN is registered to Kerv Experience Limited — the renamed Foehn, a British cloud-telephony and contact-centre provider. Foehn was one of three companies (with DoubleEdge and Metaphor IT) merged in a £30m LDC-backed deal in 2020 to create the Kerv group.

What it's used for

Voice infrastructure. The AS is tiny — three prefixes totalling about 1,000 IPv4 addresses, two observed BGP neighbours — and the reverse DNS says exactly what it carries: sgw.voipfoehn.net, a session gateway in the company's VoIP domain.

Foehn built its business on open-source telephony (Asterisk, and later its own Voxivo cloud phone platform) sold to UK businesses, so the space holds SBCs, media gateways and platform servers rather than customer access lines. There is no subscriber-pool naming and no hosting-style host numbering.

Notable

• The 185.121.16.0/22 block, announced both as a /22 and as two component /24s, is the whole estate. Voice platforms need very little address space and a lot of uptime, which is why a company of this size can run for years on a single /22.
• The AS was first seen in RIS announcing a /27 — an unusually small prefix to originate, and a sign of a network sized for signalling rather than scale.

Interesting

An operator whose product is "cloud phone systems" looks superficially like an ISP, but its addresses never touch an end user's premises: the customer's handsets sit on someone else's broadband and register inward to these gateways. What the space carries is enterprise voice infrastructure, which is why it files as business rather than telecoms access.