EIGRP and NAT

CSCO11453146 · ‎01-15-2009

Hello everybody

It is my first time writing here and I would like to thank you for spending your time on my question.

So,I am a CCNA candidate and I came up with a problem.I connected back to back two cisco routers (2610XM using the low speed serial int and 2600 using the serial and providind the clocking at 64000).The problem is that if I have nat configured,EIGRP is not working and when I use debug it shows that one router is finding the other but after a while looses the adjajency.At the show ip route, I am getting no EIGRP routes.If I use OSPF everything's working.No auto-summary is configured fo EIGRP.If I disable nat,EIGRP is working fine.Any ideas what could be the problem?

Thanks

lejoe.thomas · ‎01-15-2009

Hi Emmanouel,

It would be helpful if you could post the running-configuration when EIGRP is configured.

Lejoe

Giuseppe Larosa · ‎01-16-2009

Hello Emmanouel,

in a real world scenario a dynamic routing protocol is not used at a NAT device interface that is usually at a border router.

you can make EIGRP working by changing NAT configuration so that you can use an extended ACL.

access-list 101 deny eigrp any any

access-list 101 permit ip net wildcard any

route-map sel-nat

match ip address 101

ip nat inside source route-map sel-nat ...

What I don't understand is how OSPF works with NAT enabled.

Hope to help

Giuseppe