two routers on the same lan

Discussion in 'Cisco' started by sali, Jun 30, 2009.

  1. sali

    sali Guest

    i have cisco router to wan connection [only wan interface card], with my
    internal lan being 10.10.0.x, router being, now i need additional
    router to connect to adjacent building [with high speed etehrent lan] having
    their lan on 10.20.0.x
    is it possible to somehow attach additional router [for ex] with
    net interface to connect my lan with this adjacent building?
    i have read somewhere that there is some inter-router discovery protocol,
    and that my default router [wan] may discover and redirect traffic to this
    additional router, in case that subnet is required? of course, this my
    router should remain as default gateway

    sali, Jun 30, 2009
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  2. sali

    Rob Guest

    In your first router, configure a route to 10.20.0.x via gateway
    Make sure you have not turned off redirects.

    All your client systems will send the traffic for 10.20.0.x via their
    default gateway (your first router), which will send it on via
    its route to But it will also send an ICMP redirect packet
    to the client, which will then send the next packets directly to the

    This usually works quite well, but you have to beware that sometimes
    such redirect packets are turned off or filtered in a firewall. In that
    case all your traffic to 10.20.0.x will take an unnecessary hop via
    your first router.

    Of course you could also set a fixed route to 10.20.0.x via
    in all your client systems. But that may be a lot of work and when
    you change the network you may need to do it all over again.
    Rob, Jun 30, 2009
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