AS11205 CITY-OF-PHILADELPHIA

CITY-OF-PHILADELPHIA is the municipal network of the City of Philadelphia, Pennsylvania. It announces a single legacy /16 plus two more-specifics carved from it, all registered to the city itself.

What it's used for

Municipal government IT. The announced space is 170.115.0.0/16 with 170.115.247.0/24 and 170.115.248.0/23 deaggregated on top of it — 3 prefixes, 65,536 addresses, no IPv6, and only 2 observed BGP neighbours. That combination is the classic city-government profile: a large historical allocation carrying city departments, public-safety systems, libraries and public-facing services, multihomed across a small number of upstreams rather than peering broadly.

Notable

Every announced prefix is registered to PHILADELPHIA — the AS holder and the address holder are the same body, so there is no third-party-registrant ambiguity here. The one sampled reverse-DNS record, gscm.phila.gov, resolves under the city's own phila.gov domain, confirming that the space carries first-party city services rather than being sublet to anyone else.

Interesting

The two more-specifics announced alongside the covering /16 are a deliberate traffic-engineering choice, not an accident of registration. Announcing a /24 and a /23 on top of the aggregate lets the city steer particular services onto a particular upstream while the /16 keeps a route alive if that path fails — a pattern common in organisations that hold a large classful-era block and want to split it across links without giving up the aggregate.