AS15626 GF-UA

Some of the reverse names end in top-level domains that do not exist.

What it's used for

• A hosting network reselling space from many suppliers. Twenty-three IPv4 prefixes and twenty-three IPv6 prefixes announced from the United States, ten thousand addresses, across thirty-five observed BGP neighbours.

Notable

• Three answering names end in suffixes that are not real top-level domains, two of them an abbreviation for a kind of virtual server, so those names cannot resolve forward.
• One hostname is returned by two different addresses in two unrelated blocks, which makes it useless as an identifier for either.
• Four answering names label themselves as a subnet or a broadcast address, across three companies' domains.
• Seven separate companies appear across the netnames, registered in at least three countries, none of them matching the country the blocks are announced from.
• Nine IPv6 prefixes form a descending staircase, each one half the size of the last, nested inside a single larger block with one step of the sequence missing.
• Eighteen addresses were queried for reverse DNS and ten returned a name.

Interesting

• A reverse name in a nonexistent domain is a name that only works in one direction. It looks informative in a traceroute and confirms nothing.
• Seven suppliers behind one announcement is the shape of a reseller: the addresses are rented, the AS number is the only part that belongs to the operator.
• The IPv6 staircase is a range being handed out in halves, each customer or purpose taking the next piece down, and every step of it visible from outside.