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New Member

NAT configuration on a second Cisco router


recently we received a new Cisco 2900 router for SDSL. Because the router is not 'our property' we are not allowed to change the Cisco configuration. Previously we had a SOHO Cisco router which we configured for NAT and this worked like a charm. In the new setup (with the new router) we have put a second Cisco (1721) in between for NAT.

See the attached Word-document for an overview of the situation and the Cisco configuration.

The problem is as follows:

Incoming traffic works perfecly, only external traffic is not working.

From the console port on the NAT 1721 router it is possible to ping outside (internet) addresses. From the FTP server it is possible to reach the FastEthernet0 port on the NAT 1712 router.

I have tried several configuration, no succes. Any help would be appreciated, thanks in advance.


F. Hendricks


Re: NAT configuration on a second Cisco router

I don't see your access-list 101 anywhere to define your inside local addresses.

Kevin Dorrell


New Member

Re: NAT configuration on a second Cisco router


I don't exactly know what you mean.

In the new configuration I tried adding

the line:

ip nat inside source list 101 interface ethernet0 overload

Now it is not possible anymore to ping the outside world from the console port from the cisco 1721 NAT router.

How do you think I should configure this access-list on the NAT router. The only inside local addresses are for the FastEthernet0 port and for the Server. Thanks again.