AS15290 ZAYO-CAN-15290

Ninety-five prefixes, netnames numbered with gaps, and reverse DNS under an acquired carrier.

What it's used for

• A wholesale network carrying its own and its customers' address space. Seventy-five IPv4 prefixes and twenty IPv6 prefixes announced, twenty-one thousand addresses in total, across twenty-seven observed neighbours.

Notable

• Netnames follow one stem with a counter, but the counters seen here skip: seven, nine, fifteen and twenty-five, with one written as ZAYO-CAN--9 using two hyphens where the others use one.
• Two blocks inside the range are registered to a security company rather than the carrier, under a default netname that begins with a leading zero before the address.
• The AS handle ends in this AS number, so the identifier contains itself.
• Three of eighteen sampled addresses answered, all under a different carrier's domain, the name of a company that no longer trades under it.
• One block's registry lookup failed, so nothing can be said about who holds it.

Interesting

• Reverse DNS under a predecessor's domain dates the acquisition better than any registry field. The zone still resolves, the addresses still answer, and renaming them would break nothing except the historical record.
• Customer blocks sitting inside a carrier's numbered series is how wholesale works: the carrier announces the route, the customer holds the registration, and only the netname shows the difference.
• The doubled hyphen is a typing slip that became permanent. Netnames are set once and rarely corrected, so small errors persist for decades.