Routing question

Discussion in 'Cisco' started by coffin@isd.net, Dec 4, 2004.

  1. Guest

    I have 2 routers


    RouterA

    E0 10.1.1.252 255.255.0.0
    S0 10.53.1.1 255.255.255.252

    ip route 0.0.0.0 0.0.0.0 10.1.1.101 (this is a internet interface of a
    pix)


    Point to point t1

    RouterB

    e0 10.3.1.1 255.255.0.0
    s0 10.53.1.2 255.255.255.252

    IP route 0.0.0.0 0.0.0.0 10.53.1.1

    RouterA can ping the internet fine

    RouterB
    I can ping 10.3.1.1 of course
    I can ping 10.53.1.2
    I can ping 10.53.1.1
    I cant ping 10.1.1.252 and thus
    I cant ping 10.1.1.101 or anything else on the LAN on routerA site

    Am i missing somthing here?

    I am also running eigrp with a network of 10.0.0.0

    I am not running any nat and i think that is what i need here for
    RouterB to communicate with the the lan and default gateway
    (10.1.1.101) on RouterA's LAN.

    Any thoughts?

    Thanks
    , Dec 4, 2004
    #1
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  2. Seth Guest

    Sounds good thus far. Do the eigrp autonomous system numbers match?

    Btw, you might want to look into redistribute-static on RouterA. That way
    you wouldn't need the default route on RouterB.

    What does show ip route show? Are you learning any routes?
    Seth, Dec 4, 2004
    #2
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  3. Toby Guest

    <> wrote in message
    news:...
    >I have 2 routers
    >
    >
    > RouterA
    >
    > E0 10.1.1.252 255.255.0.0
    > S0 10.53.1.1 255.255.255.252
    >
    > ip route 0.0.0.0 0.0.0.0 10.1.1.101 (this is a internet interface of a
    > pix)
    >
    >
    > Point to point t1
    >
    > RouterB
    >
    > e0 10.3.1.1 255.255.0.0
    > s0 10.53.1.2 255.255.255.252
    >
    > IP route 0.0.0.0 0.0.0.0 10.53.1.1
    >
    > RouterA can ping the internet fine
    >
    > RouterB
    > I can ping 10.3.1.1 of course
    > I can ping 10.53.1.2
    > I can ping 10.53.1.1
    > I cant ping 10.1.1.252 and thus
    > I cant ping 10.1.1.101 or anything else on the LAN on routerA site
    >
    > Am i missing somthing here?
    >
    > I am also running eigrp with a network of 10.0.0.0
    >
    > I am not running any nat and i think that is what i need here for
    > RouterB to communicate with the the lan and default gateway
    > (10.1.1.101) on RouterA's LAN.
    >
    > Any thoughts?
    >
    > Thanks


    If you are pinging from RTRB to RTRA interface address of 10.1.1.252 it
    should be successful even if EIGRP wasn't active.

    The reasoning behind this is that The source address of the pings would be
    your outgoing interface of RTRB i.e. 10.53.1.2 and the destination address
    is 10.1.1.252.

    RTRB would route to 10.1.1.252 via the default route pointing to 10.53.1.1
    (although as this is a point to point link you would be better off for
    diagnosis reasons using the command IP ROUTE 0.0.0.0 0.0.0.0 Serial0)

    RTRA has a directly connected interface for 10.1.1.252 so this would be in
    it's routing table.

    The Echo reply would be able to get back to the original source as it is
    also on a directly connected interface for RTRA/B.

    As for NAT well this would have to be done on the PIX else you wouldn't have
    Internet connectivity at all, but is not your problem.

    Taking this at face value. either you have ACL blocking your pings or you
    are using extended pings from RTRB sourcing the pings from the ethernet and
    EIGRP isn't configured/working correctly so no return path is available or
    you are trying to ping from outside of RTRB on the ethernet or behond and
    the same reason applies.

    Regards

    Toby
    Toby, Dec 4, 2004
    #3
  4. <> wrote in message
    news:...
    >I have 2 routers
    >
    >
    > RouterA
    >
    > E0 10.1.1.252 255.255.0.0
    > S0 10.53.1.1 255.255.255.252


    You are running Variable Length Subnet Masks. Be sure to set "ip classless"
    and tell us what version software you are running.


    > ip route 0.0.0.0 0.0.0.0 10.1.1.101 (this is a internet interface of a
    > pix)
    >
    >
    > Point to point t1
    >
    > RouterB
    >
    > e0 10.3.1.1 255.255.0.0
    > s0 10.53.1.2 255.255.255.252
    >
    > IP route 0.0.0.0 0.0.0.0 10.53.1.1
    >
    > RouterA can ping the internet fine


    How? You are running RFC1918 addressing. Where is the NAT?

    > RouterB
    > I can ping 10.3.1.1 of course
    > I can ping 10.53.1.2
    > I can ping 10.53.1.1
    > I cant ping 10.1.1.252 and thus
    > I cant ping 10.1.1.101 or anything else on the LAN on routerA site
    > Am i missing somthing here?


    Yes. Summary routes. You would also need to add

    IP route 10.0.0.0 255.0.0.0 10.53.1.1

    on router A, unless you can see a route to the desired subnet in "show ip
    route" Depending on how the rest of the network is set up, and how you are
    doing route summarization.

    > I am also running eigrp with a network of 10.0.0.0


    Nore details. What does "show ip route" say? Are you learning the routes?

    > I am not running any nat and i think that is what i need here for
    > RouterB to communicate with the the lan and default gateway
    > (10.1.1.101) on RouterA's LAN.
    >
    > Any thoughts?


    Make sure IP classless is set, and check summarization. Variable Length
    Sunet Masks can be crazy.
    Phillip Remaker, Dec 4, 2004
    #4
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