NAT Cisco 2500 Series

Posted on 2006-06-13
Last Modified: 2012-06-27
Trying to  learn cisco, working with a 2514 router, trying to setup NAT. What is wrong with my config listed below.

from I can ping and (DHCP Assigned) , but not beyond on the network and vice/versa.

The router is running 12.2(3) Software.

interface Ethernet0
 ip address dhcp
 ip nat outside
interface Ethernet1
 ip address
 ip nat inside
interface Serial0
 no ip address
interface Serial1
 no ip address
ip classless
ip route
no ip http server
access-list 1 permit
Question by:jcs5003
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Expert Comment

ID: 16901615
you are missing the IP NAT command, which could be like this:

ip nat inside source list 1 interface e0 overload

The command can be varied depend on your preference.
LVL 32

Expert Comment

ID: 16902415
ip nat inside source list 2 interface e0 overload

access-list 2 permit


Author Comment

ID: 16903013

your answer worked, thanks alot....can you explain these commands? how does the source list reference the different interfaces? ( source list 2 = e0 ??)

LVL 32

Accepted Solution

rsivanandan earned 250 total points
ID: 16903557
I'll try to explain it simple;

You have 'ip nat inside' on the e1 interface and 'ip nat outside' on the e0 interface which tells the traffic coming from e1 and going out through e0 should be natted.


ip nat inside source list 2 int e0 overload

What this tells the router is that, any traffic that matches the access-list 2 should be patted using inteface e0's ip address.

The access-list 2 makes sure that all the hosts inside your network or in other words, all machines in 10.10.10.x network will match it.

Hope that is clear enough.


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