[c-nsp] DNS and NAT

[Roy]

Found it.

ip nat inside source static udp 10.10.100.20 53 xx.xx.xx.xx 53 
extendable no-payload

Roy wrote:
>
> I have done some more testing and it appears that any DNS response 
> that contains an IP address is lost.  The problem must be related to a 
> defective fixup in the NAT routine.  I haven't been able to figure out 
> how to disable the DNS fixup in IOS
>
> Roy
>
> Roy wrote:
>> I am trying to setup a Linux box behind a Cisco router that has NAT 
>> turned on.
>> I configured:
>>
>> ip nat inside source static udp 10.10.100.20 53 xx.xx.xx.xx 53 
>> extendable
>> ip nat inside source static tcp 10.10.100.20 53 xx.xx.xx.xx 53 
>> extendable
>>
>> If I do
>>
>> dig . @xx.xx.xx.xx
>>
>> From the internet, I get the proper response.  tcpdump on linux shows 
>> the packet arriving and a response packet.
>>
>> If I do
>>
>> dig domain.com @xx.xx.xx.xx
>>
>> I get no response.  tcpdump on the linux box shows a reply packet 
>> leaving it and the router responding with ICMP host unreachable.
>>
>> Software is
>>
>> IOS (tm) C1700 Software (C1700-K9O3SY7-M), Version 12.3(18), RELEASE 
>> SOFTWARE (fc3)
>>
>> Any ideas are welcome.
>>
>> Roy
>>
>>
>>
>>
>
>