multi ospf paths

Discussion in 'Cisco' started by ajn, Mar 2, 2010.

  1. ajn

    ajn Guest

    I setup my lab routers for ospf. In which I have formed adjacencies with my
    main router and remote router via serial link. All routes fine, I set a
    gateway of last resort on my main router to the interface of my VZ FiOS
    router and able to get out to the internet. I setup the nat correctly on the
    serial and ethernet interfaces and set a gateway of last resort on my remote
    router to the ip address of the main router serial interface. Hence I able
    able to get internet access from my remote segment.

    I added a second serial line connection in which I established the proper
    connections and have two ospf paths between my routers and all the proper
    adjacencies have formed. If I kill the first serial link that has the
    gateway of last resort set on, I still have connectivity to my routers but
    no internet access from the remote router.

    Hence, how to I setup up my remote router so I still have internet access if
    the serial interface is down that the gateway of last resort static route is
    set for?

    Thanks in advance for any guidance.

    ajn, Mar 2, 2010
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  2. ajn

    Mark Huizer Guest

    The wise ajn enlightened me with:
    A little config here and there might make life easier :)

    But anyway... if ser0 is your 'first' link and ser1 your 'second' link,
    you could work with routes with differend administrative distances, e.g.

    ip route ser0 240
    ip route ser1 241

    (or ip addresses instead of interfaces).
    The admin distances will put these routes above the routes learned from
    ospf, and if the ser0 is down, that route will be removed from the
    routing table

    Mark Huizer, Mar 2, 2010
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  3. ajn

    ajn Guest

    Thank you Mark,

    I will try that when I am back in my lab tomorrow. I will post configs if
    necessary, but think your answer is correct.

    I deeply appreciate your help and reply.

    ajn, Mar 2, 2010
  4. ajn

    ajn Guest

    Thank you my Friend that was the correct answer and now that works, I can
    shut down a link and still keep the internet connection and see the one
    route go away.

    Again I appreciate your courteous reply.

    ajn, Mar 2, 2010
  5. ajn

    ajn Guest

    I learned how to use the

    default-information originate command and seemed to make a nice solution

    Thank you for your help, I learned a few new things, and not sure how to
    approach this in OSPF.
    ajn, Mar 4, 2010
  6. ajn


    Jan 6, 2010
    Likes Received:
    hello! one of the solutions if you want to work your default routes with static routes is to create a Lo in your "next hop router" and point your static default route to the loopback of the next hop router... then advertise the Lo in your routing protocol.
    The Lo will never go down if one of your links goes down permiting the router with the static route forward packets to the default gateway.
    bryanpalacios, Mar 5, 2010
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