Perimiter router woes

Discussion in 'Cisco' started by Mikhael47, Jun 16, 2004.

  1. Mikhael47

    Mikhael47 Guest

    I have two perimeter routers that both have interfaces on the
    xxx.xxx.xxx.xxx network. Router A uses nat to translate to the
    yyy.yyy.yyy.yyy network and router B translates to the zzz.zzz.zzz.zzz
    network.

    On router B I had the external interface set to xxx.xxx.xxx.121. I changed
    that interface address to xxx.xxx.xxx.113 and setup a static nat on router A
    to translate xxx.xxx.xxx.121 to yyy.yyy.yyy.64. Whenever I ping the .121
    address from the internet i get replys from Router B instead of Router A. (I
    have an access list that blocks the ping and returns Destination Net
    unreachable).

    What do I have to do to get router A to accept packets for xxx.xxx.xxx.121?
    Router A is a 2621 and router B is a 1710. I have an upstream router on the
    xxx.xxx.xxx.xxx network that is out of my control (I can reboot it but
    that's it.) Is the upstream router causing the problem?

    Mike
     
    Mikhael47, Jun 16, 2004
    #1
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  2. Mikhael47

    Hansang Bae Guest

    In article <krZzc.30331$>, mikhael47
    @hotmail.com says...
    > I have two perimeter routers that both have interfaces on the
    > xxx.xxx.xxx.xxx network. Router A uses nat to translate to the
    > yyy.yyy.yyy.yyy network and router B translates to the zzz.zzz.zzz.zzz
    > network.
    >
    > On router B I had the external interface set to xxx.xxx.xxx.121. I changed
    > that interface address to xxx.xxx.xxx.113 and setup a static nat on router A
    > to translate xxx.xxx.xxx.121 to yyy.yyy.yyy.64. Whenever I ping the .121
    > address from the internet i get replys from Router B instead of Router A. (I
    > have an access list that blocks the ping and returns Destination Net
    > unreachable).
    >
    > What do I have to do to get router A to accept packets for xxx.xxx.xxx.121?
    > Router A is a 2621 and router B is a 1710. I have an upstream router on the
    > xxx.xxx.xxx.xxx network that is out of my control (I can reboot it but
    > that's it.) Is the upstream router causing the problem?


    Couple of things you can try. 1) 'clear arp' on the B router which
    will send a gratuitous arp to the upstream router. 2) Turn off the B
    router and wait four hours for default arp timers on upstream Cisco
    routers go time out.

    I'm assuming you've cleared the NAT tables on the B router.

    --

    hsb

    "Somehow I imagined this experience would be more rewarding" Calvin
    *************** USE ROT13 TO SEE MY EMAIL ADDRESS ****************
    ********************************************************************
    Due to the volume of email that I receive, I may not not be able to
    reply to emails sent to my account. Please post a followup instead.
    ********************************************************************
     
    Hansang Bae, Jun 16, 2004
    #2
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  3. Mikhael47

    Mikhael47 Guest

    I cleared the arp on B with no avail.. I called my ISP and got them to clear
    the arp entry on their side and it worked.

    Thanks for your prompt reply

    Mike

    "Hansang Bae" <> wrote in message
    news:...
    > In article <krZzc.30331$>, mikhael47
    > @hotmail.com says...
    > > I have two perimeter routers that both have interfaces on the
    > > xxx.xxx.xxx.xxx network. Router A uses nat to translate to the
    > > yyy.yyy.yyy.yyy network and router B translates to the zzz.zzz.zzz.zzz
    > > network.
    > >
    > > On router B I had the external interface set to xxx.xxx.xxx.121. I

    changed
    > > that interface address to xxx.xxx.xxx.113 and setup a static nat on

    router A
    > > to translate xxx.xxx.xxx.121 to yyy.yyy.yyy.64. Whenever I ping the

    ..121
    > > address from the internet i get replys from Router B instead of Router

    A. (I
    > > have an access list that blocks the ping and returns Destination Net
    > > unreachable).
    > >
    > > What do I have to do to get router A to accept packets for

    xxx.xxx.xxx.121?
    > > Router A is a 2621 and router B is a 1710. I have an upstream router on

    the
    > > xxx.xxx.xxx.xxx network that is out of my control (I can reboot it but
    > > that's it.) Is the upstream router causing the problem?

    >
    > Couple of things you can try. 1) 'clear arp' on the B router which
    > will send a gratuitous arp to the upstream router. 2) Turn off the B
    > router and wait four hours for default arp timers on upstream Cisco
    > routers go time out.
    >
    > I'm assuming you've cleared the NAT tables on the B router.
    >
    > --
    >
    > hsb
    >
    > "Somehow I imagined this experience would be more rewarding" Calvin
    > *************** USE ROT13 TO SEE MY EMAIL ADDRESS ****************
    > ********************************************************************
    > Due to the volume of email that I receive, I may not not be able to
    > reply to emails sent to my account. Please post a followup instead.
    > ********************************************************************
     
    Mikhael47, Jun 16, 2004
    #3
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