USADOTGOV.NET Root Problems?

[Danny Mayer]

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