AS13026 K-WLAN-AS

Half the reverse zone has its third octet frozen at the block's base address.

What it's used for

• An Austrian wireless internet provider. 1,536 addresses across two IPv4 prefixes, one observed BGP neighbour, and no IPv6 announced.

Notable

• 91.222.92.0/22 carries netname XINON-91-222-92-0, registered to XINON GmbH; 91.224.70.0/23 carries K-WLAN-NET, registered to an individual.
• All six sampled addresses answered, across two domains: steirerlan.at and k-wlan.at.
• 91.222.93.0 answers 91.222.92.0.steirerlan.at and 91.222.93.255 answers 91.222.92.255.steirerlan.at, both naming the wrong third octet.
• 91.222.94.254 and every address in the second block answer with their own address.

Interesting

• Two addresses in the /22 are named after the block's base rather than themselves. The zone was generated with the third octet hardcoded at 92, so everything in the first /24 worth of the range claims an address it does not have, while the rest of the block is correct. Nothing breaks, because almost nothing verifies that a reverse name resolves back to the address it came from. The same template error has turned up elsewhere in this sweep, which suggests a common tool rather than a common mistake.
• The netname XINON-91-222-92-0 writes the block's own address into its name. It is redundant, since the record is already keyed by the prefix, and it survives handover between holders in a way a company name would not.
• Two domains for two blocks, one of them a regional brand and one the operator's own, is what a small wireless provider looks like after absorbing a neighbour.