ip unnumbered

Discussion in 'Cisco' started by tweety, Jan 28, 2009.

  1. tweety

    tweety Guest

    Hi folks,

    Im a newbie to cisco hardware and configuration.

    I was wondering if there was anyway i could do an ip unnumbered sort
    of set up for the following.

    I am being presented with a leased line via ethernet, i wil terminate
    this on fa0/0, i want fa0/1 to be the LAN interface, however i need
    that to have the same ip as fa0/0, same sort of idea with a leased
    line provided via x21. Int s0/0 ip unnumbered fastethernet 0/1. I know
    i ban't do an ip unnumberered on a non point to point multi access

    Anyone any ideas? Maybe a loopback with some policy routing?

    Im totally stumped, any pointers would be apprecited guys, thanks.

    tweety, Jan 28, 2009
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  2. tweety

    bod43 Guest


    It can be a bit confusung (I found) so I have guessed
    at a config - not typed it in to verify.

    bridge irb
    bridge 1 protocol ieee
    bridge 1 route ip

    ! type in again - they are order sensitive and this fixes it.
    bridge irb
    bridge 1 protocol ieee
    bridge 1 route ip
    ! check you have no errors reported

    int bvi 1
    ip address whatever.you.want mask...

    int fa 0/0
    no ip address
    bridge group 1

    int fa 0/1
    no ip address
    bridge group 1
    bod43, Jan 28, 2009
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  3. tweety

    tweety Guest

    Thanks i will give it a try, so routing wise i can point a defaul
    route to int fa0/0 etc?

    Your a diamond for replying :)
    tweety, Jan 28, 2009
  4. tweety

    tweety Guest


    When i use the above config i cant send a default route to e0/0

    int e0/0
    no ip address
    bridge-group 1

    int e0/1
    no ip address
    bridge-group 1

    int bvi1
    ip address

    Anyone any ideas?

    Thanks for any input

    tweety, Jan 28, 2009
  5. tweety

    bod43 Guest

    You will need to make the default gateway of your
    internal devices the address of the ISP's router.
    They will tell you what it is.

    Perhaps you should really be doing NAT
    on this box. I did not think beyond your
    detailed request.

    If you explain in detail what you are trying to do
    and what you have then perhaps we can assist.

    You can mangle the iP addresses that you have
    if you like but leave any octets not
    covered with a 255 mask alone.


    change it to something like

    and keep changes consistent.
    bod43, Jan 29, 2009
  6. tweety

    tweety Guest

    Hi Bod thanks for your reply,

    I have a leased line from site A to site B, site A address of router
    port terminating leased line is, the site B address is
    lets say, this used to run via ip unnumbered on the serieal
    interfaces on both routers, however the ISP have provided Fastethernet
    presentation, i cannot do ip unnumbered on these interfaces. So at
    site A i need fa 0/0 to be /24 however fa 0/1 must be in
    this range also as it hops traffic onto the /24 lan
    towards a firewall at

    I want traffic destined for the /24 net to exit fa 0/0
    interface and all other ( default ) traffic to exit the fa 0/1
    interface towards the firewall. I need both my interfaces using the address for lan and wan access just like when using ip
    unnumbered on serial interface. Does this help?

    FW<<R1 <<leased line >>R2

    I appreciate any help/pointers you can give me.

    tweety, Jan 29, 2009
  7. tweety

    bod43 Guest

    Forget the bridging.

    Just use a new network (or subnet) for the new link.
    Anything that is not is use in your network.

    e.g. for one end for the other

    You will need to change the routes too.

    ip route xxxxx xxxxx next.hop.address
    bod43, Jan 29, 2009
  8. tweety


    Nov 11, 2011
    Likes Received:
    Hi all
    Please can any one through a light on unnumbered pppoe implementation

    i am not gettinfg a head or tail from the searches that i have made on google.
    what ever i search about unnumbered pppoe it gets stopped at "ip unnumbered" of cisco IOS

    the big question cant any one implement "ip unnumbereed" command on linux kernel?
    I tried but failed by showing message as
    "Object "unnumbered" is unknown, try "ip help"."

    iam new to linux and pppoe
    please clarify me about unnumbered pppoe

    1) is there something like unnumbered pppoe server?

    2) suppose i have lan interface as "eth0" and wan interface as "eth1" and "eth1" interface is directly connected to pppoe server, Then am i supposed to get ip from pppoe server as for virtual interface ppp0 ?
    if yes then i have seen in google some where that ppp0 interface ip is set to etho (lan) interface. and eth1 has no ip
    if no then please explain me what should i have to do to implement unnumbered pppoe.

    3) iam having linux as os and my i have rppppoe ..Does these two are enough to implement unnumbered pppoe?
    poori401, Nov 11, 2011
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