Why don't you NAT on the one of the 3640's serial interfaces and overload on the valid IP. Then have a default route set on the 1720 to point to the 3640.just an idea.
is the internet pipe coming into the 3640??how are the 1720 and 3640 connected??are you using a firewall??there are a lot of questions that need answers first
Step Command Purpose 1 . ip nat pool name start-ip end-ip {netmask netmask | prefix-length prefix-length} Define a pool of global addresses to be allocated as needed.2 . access-list access-list-number permit source [source-wildcard] Define a st...
