BGP question

Discussion in 'Cisco' started by supernet, Dec 30, 2005.

  1. supernet

    supernet Guest

    I have 2 routers connect to 2 ISPs:

    ISP1 router--------My router1------My router2---------ISP2 router



    My router1 configuration:

    router bgp 11111

    no synchronization

    no bgp log-neighbor-changes

    network 17.11.0.0

    neighbor 69.231.141.153 remote-as 12345

    neighbor 17.11.25.11 remote-as 11111

    no auto-summary



    My router2 configuration:

    router bgp 22222

    no synchronization

    no bgp log-neighbor-changes

    network 17.11.0.0

    neighbor 167.13.192.145 remote-as 54321

    neighbor 17.11.25.12 remote-as 22222

    no auto-summary



    I noticed my router2 routing table keeps changing and caused connectivity
    problems. It sometimes gets routes from ISP1 router. How does it happen? My
    router2 does not have direct session with ISP1 router. Anyone can help me?



    Here is part of the routing table on my router2:

    B 217.170.115.0/24 [20/0] via 167.13.192.145, 2w1d

    B 216.221.5.0/24 [20/0] via 167.13.192.145, 1w1d

    B 210.51.225.0/24 [20/0] via 167.13.192.145, 2w1d

    B 209.136.89.0/24 [20/0] via 167.13.192.145, 2w1d

    B 209.34.243.0/24 [20/0] via 167.13.192.145, 2w1d

    B 205.204.1.0/24 [20/0] via 167.13.192.145, 6d23h

    B 204.255.51.0/24 [20/0] via 167.13.192.145, 2w1d

    B 204.238.34.0/24 [20/0] via 167.13.192.145, 2d14h

    B 204.221.17.0/24 [20/0] via 167.13.192.145, 2w1d

    B 204.17.221.0/24 [20/0] via 167.13.192.145, 2w1d

    B 203.238.37.0/24 [20/0] via 167.13.192.145, 2w1d

    B 203.34.233.0/24 [200/0] via 69.231.141.154, 00:00:43 (why this???)
     
    supernet, Dec 30, 2005
    #1
    1. Advertising

  2. In article <>,
    "supernet" <> wrote:

    > I have 2 routers connect to 2 ISPs:
    >
    > ISP1 router--------My router1------My router2---------ISP2 router
    >
    >
    >
    > My router1 configuration:
    >
    > router bgp 11111
    >
    > no synchronization
    >
    > no bgp log-neighbor-changes
    >
    > network 17.11.0.0
    >
    > neighbor 69.231.141.153 remote-as 12345
    >
    > neighbor 17.11.25.11 remote-as 11111
    >
    > no auto-summary
    >
    >
    >
    > My router2 configuration:
    >
    > router bgp 22222
    >
    > no synchronization
    >
    > no bgp log-neighbor-changes
    >
    > network 17.11.0.0
    >
    > neighbor 167.13.192.145 remote-as 54321
    >
    > neighbor 17.11.25.12 remote-as 22222
    >
    > no auto-summary
    >
    >
    >
    > I noticed my router2 routing table keeps changing and caused connectivity
    > problems. It sometimes gets routes from ISP1 router. How does it happen? My
    > router2 does not have direct session with ISP1 router. Anyone can help me?


    It gets them from router1, via iBGP. By default, BGP doesn't change the
    next-hop when passing routes in iBGP. Router2 should learn the route to
    ISP1 Router through your IGP, so you shouldn't lose connectivity because
    of this. If there's some reason why this route can't be passed in your
    IGP, you should configure the iBGP neighbor sessions with the
    "next-hop-self" option.

    --
    Barry Margolin,
    Arlington, MA
    *** PLEASE post questions in newsgroups, not directly to me ***
    *** PLEASE don't copy me on replies, I'll read them in the group ***
     
    Barry Margolin, Dec 30, 2005
    #2
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Spuds

    BGP filtering question

    Spuds, Jul 17, 2003, in forum: Cisco
    Replies:
    0
    Views:
    1,318
    Spuds
    Jul 17, 2003
  2. Simon Chamberlain

    Simple BGP Question

    Simon Chamberlain, Feb 24, 2004, in forum: Cisco
    Replies:
    1
    Views:
    448
    Craig Johnson
    Feb 24, 2004
  3. Christian Lox
    Replies:
    4
    Views:
    1,491
    Klaus Thielking-Riechert
    Jul 4, 2004
  4. harald rüger
    Replies:
    0
    Views:
    549
    harald rüger
    Oct 25, 2004
  5. papi
    Replies:
    4
    Views:
    2,240
    theapplebee
    Sep 8, 2009
Loading...

Share This Page