AS13977 CTELCO - Fidium

The IPv6 announcement is a textbook binary decomposition, and the reverse names still carry a retired brand.

What it's used for

• A residential and business broadband network. 492,544 addresses across 263 IPv4 prefixes plus 29 IPv6 prefixes, with 51 observed BGP neighbours.

Notable

• The largest blocks are 70.8.0.0/16, 163.252.0.0/16, 69.53.0.0/17 and 216.212.0.0/18, all under the netname CC-4441 and registered to Fidium.
• The IPv6 space is 2604:6e00::/40, announced alongside a descending ladder of its own sub-blocks: two /48s, then /47, /46, /45, /44, /43, /42 and /41.
• Reverse names take the form 70-8-191-254.mnchnh.fidium.ccidns.net, with a six-character site code ending in a two-letter state abbreviation.
• One sampled address answered to pool-70-105-247-254.port.east.myfairpoint.net instead.
• 72.95.96.0/19 registers to American Registry for Internet Numbers under the netname NET72.

Interesting

• Each of those IPv6 prefixes covers exactly the space the previous ones do not, so together they tile the /40 completely. Announcing a block that way, rather than as one aggregate, means every piece can be steered independently while the whole remains contiguous.
• The site codes name three different states in a sample of six, which is what a regional telephone company that grew by acquisition looks like from the reverse DNS alone.
• One address still answers under an older brand's domain. Renaming a company is easy; renaming every address in half a million is a migration that runs for years, and the stragglers are visible to anyone who queries them.
• The block registering to the registry itself, rather than to a customer, means the lookup landed on a parent allocation instead of an assignment.