On 2013/12/02 15:27, Marcus Taylor wrote: > We hit a similar problem with Critical Path [cpcloud.co.uk] - it was > found that their DNS lookup would be in uppercase and a bug in a Cisco > ASA firewall in the path was dropping the request. > > Not sure if this is a similar issue.
Looks like it. $ dig +short 242.22.0.134.in-addr.arpa. ptr @ns1.c-it.co. shared4.wirehive.net. $ dig +short 242.22.0.134.in-addr.ARPA. ptr @ns1.c-it.co. ;; connection timed out; no servers could be reached > A while ago CISCO released an update to their IOS firmware that > introduced a bug. As a consequence, it no longer accepted PTR lookups > that used uppercase alphabetic characters. Interesting. Note that this will also break lookups for people using resolvers that implement draft-vixie-dnsext-dns0x20-00 (for example unbound with the use-caps-for-id option).
