AS12613 — FIREBRICK-AS

AS12613 announces 1 IPv4 prefixes covering 256 addresses and 0 IPv6 prefixes.

About this network

A /24 whose reverse records answer with the question they were asked.

What it's used for

• Corporate connectivity for a British router manufacturer. 256 addresses in a single IPv4 prefix and no IPv6 announced.

Notable

• The whole inventory is 193.17.12.0/24, netname FIREBRICK, with no country prefix and no date.
• All three sampled addresses answered: 193.17.12.64 returns 64.12.17.193.in-addr.arpa, 193.17.12.127 returns 127.12.17.193.in-addr.arpa, and 193.17.12.190 returns 190.12.17.193.in-addr.arpa.
• The registry contacts are Firebrick Hostmaster, Firebrick Limited, and AAISP Support — a second company's support desk.
• First seen in routing data in December 2003, a real date rather than the floor of the archive.

Interesting

• Those reverse records point at their own names. A lookup of 193.17.12.64 is a query for the record at 64.12.17.193.in-addr.arpa, and the answer that comes back is that same string. It is a valid record that conveys nothing, produced by a zone generated from a template where the target field was filled with the name instead of a hostname.
• Anything doing a forward-confirmed check on these addresses gets an answer it cannot resolve back, so the record is worse than silence for that purpose while looking like a configured network to anything counting responses.
• A hardware company keeping 256 addresses and an AS number since 2003, with an internet provider's support desk listed as a contact, is what a long working relationship looks like in the registry: two organisations, one record, no way to tell from the outside which one answers the phone.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.

Announced prefixes

• 193.17.12.0/24

Upstream networks

• AS20712 Andrews & Arnold Ltd

Adjacent networks

• AS20712 Andrews & Arnold Ltd