AS11647 SENTEX-NET

SENTEX-NET is Sentex Communications, a long-established independent internet provider based in Cambridge, Ontario, serving southwestern Ontario. RIS sees 32 IPv4 prefixes and about 23,300 addresses, 2 IPv6 prefixes (2607:f3e0::/32 and a /48), and 14 observed BGP neighbours.

What it's used for

Regional access and business connectivity. The reverse DNS is the clearest evidence of what the space carries: names like p4j.xDSL-1mm.sentex.ca, dimplex-dsl.sentex.ca and 67-43-136-5.agas1a-dynamic.dsl.sentex.ca are subscriber access, with an explicitly dynamic DSL pool among them, while dw3-lo0.sentex.ca, dw4blo0.sentex.ca and ipsec-test.sentex.ca are the operator's own routers and service hosts. This is an eyeball network with a substantial business-access side, not a pure enterprise and not a wholesale carrier — 14 neighbours is a mid-sized ISP with several upstreams and peering, an order of magnitude short of a transit provider.

The prefix registrants deserve a careful read rather than an alarm. Most blocks register to Sentex itself (SENTEXCO, SENTEXCO2), but three register to other companies: Com Dev Ltd., Toy Com, and Junior Mine Services Ltd. These are not a leased-address tell. They are ordinary SWIP reassignments to named business customers — the pattern of an ISP that has been assigning space to local firms for decades — and the reverse DNS confirms it: 199.71.252.5 answers as eldon.toy.com, a customer running its own naming, while addresses inside the Junior Mine block still answer under sentex.ca.

Notable

Com Dev was a Cambridge, Ontario space-hardware manufacturer, which is about as local a customer as a Cambridge ISP could have. Customer names preserved in the registry are a kind of fossil record of a regional provider's history.