Forum Replies

  1. Hi Sims,

    Let’s say you have a small network with a couple of routers. One router is connected to an ISP router for Internet access. On this router, you could advertise a default route in your OSPF network.

    When there is no matching route in the routing table, the default route will be used and your traffic will be forwarded towards the ISP.


  2. Shawn,
    Yes, you can do this, sort of :slight_smile:

    Remember that a requirement for OSPF is that all members in the same area must have identical databases (and I presume that your DMVPN hub and spokes are in the same area). So the best you are going to be able to do is keep that default route from getting installed in the routing table, even though it will still be present in the OSPF database. I recommend using a prefix-list to do it. Here’s a sample:

    (config)#ip prefix-list PL_NODEFAULT deny
    (config)#ip prefix-list PL_NODEFAULT permit le 32
    ... Continue reading in our forum

  3. Suppose If you are using bgp and ospf in a network what is the need of using default route in ospf ? .BGP will take care of default route to isp.

  4. I had a question.

    1. with Static default route we configure something like the following:

    ip route xxx.DestinationAddress.xxx.xxx

    1. If it was EIGRP and we had the following manually configured default route to advertise in EIGRP we would then use the following:

    R2(config)#router eigrp AS#

    with OSPF I did not see something similar is that because you just did not put in the full configuration or because OSPF just uses that statement:

    default-information originate always

    I would think it would need a manual e

    ... Continue reading in our forum

  5. Hi Brian,

    If you use default-information originate always then OSPF advertises a default route, even if you don’t have a default route in your local routing table. The “problem” with this is that you “attract” traffic to destinations that you don’t have a route for. In reality, you probably use this on some edge router that is connected to the Internet and you have a default route pointing to your ISP.

    If you wonder about something like this, instead of trying to “think it through”…boot up some routers, configure this on OSPF and see what happens when you send

    ... Continue reading in our forum

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