How to use a Cisco 877 to route traffic to a different router

Posted on 2009-12-21
Last Modified: 2012-05-08
We have a client that has two ADSL routers - one is a Cisco 877 that we installed, the second has a slow 512k connection on a Cisco 837 that belongs to the client's supplier; we have no control of or access to it.

At the moment all client computers that need to access the supplier's Intranet have the supplier's router (say for the sake of argument) set as the default gateway.  This means they can access the Intranet (presumably over a VPN to the supplier - say at, but other Internet traffic is slow.

Now we can use a "ROUTE" command in Windows on the PCs to direct the traffic to the correct router - but it would be better to do this in the router, if possible.

So how do we configure the new Cisco 877 ( so that if traffic comes to it that's destined to the supplier Intranet (, it sends it over to the supplier router (

Also, is it a good or bad idea to configure it this way?

Thanks in advance!
Question by:David Haycox
    LVL 33

    Accepted Solution

    You should set the default gateway on the client PC's to be your 877.  On the 877, it's default gateway should be the Internet (either just goes out the Internet interface, or directed to your ISP's gateway - either way this should be setup correctly already).

    Then on the 877, you add a route to direct to (the 837).

    I'm a little foggy on the exact command  try "ip route ?" or "route ?" for help while logged in to router in config mode, on an older Cisco router it'd be:
    <login with password>
    <enter enable password>
    configure terminal
    ip route
    LVL 33

    Expert Comment

    by:Todd Gerbert
    Double checked Cisco's documentation, that command above outta do it:
    LVL 1

    Author Comment

    by:David Haycox
    Fantastic!  Just tried it on a test 857, works a treat.  I had a suspicion it would be straightforward (after all, it's a router, so routing shouldn't be hard), but it's always worth asking someone who knows better before you break something... thanks!!
    LVL 1

    Author Comment

    by:David Haycox
    Works great, thanks!

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