IPv6-related (?) Bind issue

[Yannis Nikolopoulos]

Hello all,

we've encountered a weird problem on our dual-stack (anycast) resolvers 
and I'm wondering if anyone else has experienced anything similar. 
Basically, we're getting many SERVFAIL responses for domains not in 
cache. The weird part: if the domain does not exist in the cache, a 
SERVFAIL response is produced (not all of the times) without the 
resolver querying the auth NS (no outgoing communication is attempted).

More DNS-specific info about the issue (and the setup):
https://lists.isc.org/pipermail/bind-users/2014-March/092706.html
https://lists.dns-oarc.net/pipermail/dns-operations/2014-March/011385.html

I'm posting here because I'm quite convinced that the issue is IPv6-related

cheers,
Yannis