On 7/24/2010 5:10 AM, Warren Kumari wrote: > > On Jul 23, 2010, at 2:37 PM, Danny Mayer wrote: > >> On 7/22/2010 11:08 PM, Merton Campbell Crockett wrote: >>> Thanks for the confirmation that the problem was related to DNSSEC. >>> >>> I didn't see your message until I got home from work; however, I did >>> find the root of the problem late this afternoon. At each of our >>> Internet egress and ingress points, we have Cisco ASA devices sitting in >>> front of a pair of redundant firewalls. Each ASA is configured with the >>> default DNS inspect policy that doesn't accept fragmented UDP packets. >> >> Why would any inspection policy not allow fragmented UDP packets? >> There's nothing wrong with that. > > > Because it's "hard".... The issue is that then you need to buffer fragments until you get a full packet -- which leaves you open to attacks that send a bunch of fragments but leave one of them out. > > Vendors like to avoid reassembling fragments by default, because it makes their performance numbers better....
At the expense of correct behavior and loss of real performance. Danny _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
