Multiple routers with same gateway; it all works but for. . .

Discussion in 'Cisco' started by barret bondon, Apr 18, 2012.

  1. Multiple routers with same gateway; it all works but for. . .

    We have 8 external static IP's, and 8 small routers from various vendors. A
    number of these got set to for their inside gateway. When I plug
    into a lan port now on , say, a Belkin and try to manage it I'll find myself
    on , say, a Dlink.

    How to deal with this ? At the moment I unplug the offending router and work
    on the one I wish , but that seems rather silly. . . .

    Interestingly the internal system of networks and devices all function. Any
    thoughts short of ripping it all out and starting new, welcome.
    barret bondon, Apr 18, 2012
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  2. This setup works at all? I'd expect lots of brokenness in this setup.

    How'd any workstation get data out the correct gateway if they are all
    the same IP address? There must be constant ARP refresh and updates
    going on all the time, many dropped packets?

    You could update each router with a unique inside IP address, that way
    you could address them, but that would probably break things further
    in this magic setup, as I don't know what selection is used to find
    the correct gateway out.

    Yes, I'd rip it all out, put in a decent firewall device that allowed
    control over multiple external NAT mapping so you can have one
    gateway, the correct static mapping for what you want, etc.
    Doug McIntyre, Apr 18, 2012
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  3. barret bondon

    Mark Huizer Guest

    The wise barret bondon enlightened me with:
    What is your rationale behind having 8 different routers just for
    dealing with 8 external IP addresses? Is that for testing things? Or is
    there no other reason except for "dunno, it kinda works and it was

    In the second case: indeed: take 1 decent router (or 2 for failover
    using stuff like VRRP, HSRP, CARP, whatever) and configure it the right

    If you really need to have 8 routers, check logfiles from your computers
    or perhaps your switches, they should be going mad with messages about
    multiple MAC addresses using the same IP address. Take the MAC address,
    use any MAC=prefix-to-vendor mapping page on the internet, and fix the
    stuff to use different IP addresses, and try to not go insane while
    doing that.

    Mark Huizer, Apr 18, 2012
  4. barret bondon

    Nick Guest

    'rather silly' is something of an understatement. Giving the routers
    different IP addresses seems like the obvious answer to me. Is there some
    kind of IP address tax where you are? What exactly are you trying to do?
    Well if you're going to dismiss the only sensible answer...
    Well quite :)... but if the OP wants to keep the network similar and the
    number of clients permit he could do as in his other interesting post
    and split 192.168.0.x into eight subnets.
    Nick, Apr 20, 2012
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