[c-nsp] cisco nat breaks sonicwall

[Adam Greene]

Hi,

Having a weird issue where NAT on a Cisco 1841 (IP Base 12.4(22)T) 
prevents traffic from flowing through multiple models of Sonicwalls.

On the 1841:  ip nat inside source list 102 interface Dialer1 overload

The NAT works. Clients on the LAN can get to anything out on the 
Internet. But when they try to get to hosts out on the Internet that are 
behind Sonicwalls, the traffic fails. The weird thing is, you can telnet 
from LAN clients to servers behind the Sonicwalls, on various ports (25, 
80, 143, 443, 993) but when attempting to access the Sonicwall hosts 
using a web browser, the connection fails. This is from multiple LAN 
clients (PCs and mobile devices).

Anyone seen this behavior before?

We have set MTU to 1404 on all interfaces of the 1841 ... does not help.

When we do NAT on an ASA 5500 instead, no problem, clients can connect 
to servers behind the Sonicwalls fine.

Is there some feature I should enable on the 1841? Stumped ...

Thanks,
Adam