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passthough traffic on router interface

this is a 1721 router terminiating a t1. what i am looking for is not having to use an ip on the fe0 interface. is there any way to do this without assigning an ip to the inside address and just passing traffic through the interface from behind it? also are there any security implications behind this?

interface FastEthernet0

no ip address

speed auto


interface Serial0

ip address xxxxxxxxx

no fair-queue


ip classless

ip route xxxxxxxx

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Re: passthough traffic on router interface


I am not clear what you are trying to accomplish but I do not think that you want to do it this way. If you configure FastEthernet0 with no ip address, then the router will not send IP traffic over that interface.

If you are trying to conserve address space I have seen routers in situations similar to this which configure serial0 with ip unnumbered fastethernet0, and put the IP address on the FastEthernet. This does require some coordination with the router on the other end of the T1.

If that is not the solution that you are looking for, then perhaps you can clarify your environment and what you are trying to accomplish.