nat and asymmetric routing

Discussion in 'Cisco' started by linguafr, Apr 23, 2007.

  1. linguafr

    linguafr Guest

    Is it possible to nat outbound (using same addresses) out a different
    interface than the incoming interface? The lan default gw is on the
    preferred outbound path so traffic would have to reflect off that int
    and get natted. The ISP for the outbound path is partnered with the
    service provider providing the inbound path so they'll honor the
    "foreign" block.

    linguafr, Apr 23, 2007
    1. Advertisements

  2. I'm not sure if I understand your question correctly, but most likely you
    need a feature named "nat on a stick". It allows you to do NAT translation
    to a packets BEFORE they hit the "outside" interface.

    Briefly, how it works:

    1. You create a loopback interface, configure it with IP address, and define
    as "ip nat outside"
    2. You create PBR (policy based routing), to send a packets to loopback
    3. After packet hits a loopback interface, and get NATed, packet gets back
    to a routing engine to be routed normal way.
    4. You create another PBR for returning traffic.

    Good luck,

    CCNP, CCDP, CCSP, Cisco Voice, MCSE W2K, MCSE+I, Security+, etc.
    CCIE R&S (in progress), CCIE Voice (in progress)
, Apr 24, 2007
    1. Advertisements

  3. linguafr

    linguafr Guest

    Thanks mike. That's what TAC suggested as well. Pretty clever.
    linguafr, Apr 24, 2007
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.