route-map to override default gateway

Discussion in 'Cisco' started by, Apr 20, 2006.

  1. Guest


    I am in the process of switching backbone providers and for a time will
    have two ISPs connected to my cisco 3600.

    1st on a t1
    2nd on a atm pvc

    I have been operating on the 1st using static routes pionting
    to the serial interface, now I want to config my servers on the lan
    with IPs provided by the 2nd ISP so each server will have two IPs, one
    from the 1st and one from the 2nd.

    So how do I get traffic on the 2nd ISP's IPs to only traverse the atm

    I though of doing a route-map as copied below, which looks to work for
    traceroute and ping, but any tcp/udp traffic stalls. It seems to send
    one packet and then get hung.

    Thank you for your advice!


    access-list 1300 remark Provides matching of CIT addresses for atm pipe
    access-list 1300 permit
    access-list 1300 permit
    access-list 1300 permit

    route-map gotosprings permit 10
    match ip address 1300
    set ip next-hop <- 2nd isp end of the atm pvc

    int f0/0 <- this int has a primary ip from the 1st isp and a secondary
    from the 2nd
    ip policy route-map gotosprings
    ip route-cache policy
    , Apr 20, 2006
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  2. Merv

    Merv Guest

    if you have cef enabled then remove the " ip route-cache policy"
    command as that is for fast-switching PBR which is slower than CEF PBR
    Merv, Apr 20, 2006
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  3. Guest


    Thanks for the info...

    I turned of cef "no ip cef", but it did not make any difference.

    I also tried making default routing a policy only decision and removed
    all the default routes like this:
    route-map findgateway permit 10
    match ip address 1300 <- matches source ip's from 2nd isp
    set ip default next-hop b.b.b.b
    route-map findgateway permit 20
    match ip address 1301 <- matches source ip's from 1st isp
    set ip default next-hop a.a.a.a

    1st ISP worked, but 2nd did not. I even shutdown the 1st ISP
    interfaces just to make sure it wasn't through a kink into the works,
    but no go.

    Any other ideas?

    Could there be a ACL or policy upstream on the 2nd ISP causing

    Thank you,
    , Apr 22, 2006
  4. Guest

    I fixed the problem.

    Turned out to be an ATM cloud issue with the telco that was dropping
    packets over 500 bytes. Once that was fixed by the telco rebuilding the
    path, everything worked!

    A few notes on cpu utilization and route-map.

    When running CEF and route-map, make sure to issue no ip route-cache
    cef on the interface that is doing route-map and also add ip
    route-cache policy.

    , Apr 25, 2006
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