Hello guys,
there has been a request in our issue tracker [1], to enable
IPV6_USE_MIN_MTU socket option [2] for IPv6 UDP sockets in Knot DNS.
This option makes the operating system to send the responses with a
maximal fragment size of 1280 bytes (minimal MTU size required by IPv6
specification).
The reasoning is based on the draft by Mark Andrews from 2012 [3]. I
wonder if the reasoning is still valid in 2016. And I'm afraid that
enabling this option could enlarge the window for possible DNS cache
poisoning attacks.
We would appreciate any feedback on your operational experience with DNS
on IPv6 related to packet fragmentation.
[1] https://gitlab.labs.nic.cz/labs/knot/issues/467
[2] https://tools.ietf.org/html/rfc3542#section-11.1
[3] https://tools.ietf.org/html/draft-andrews-dnsext-udp-fragmentation-01
Thanks and regards,
Jan
I would like to thank Jan Včelák for submitting the gnutls30 package
into EPEL 6. This allows one to build Knot 2 for RHEL/CentOS 6 without
having to hunt down any dependencies. We still run CentOS 6 and it's
useful to be able to upgrade to Knot 2 on our servers. Thanks Jan!
Regards,
Anand