10 Replies Latest reply: May 17, 2012 7:25 AM by Brian RSS

    Bgp problem

    Sohaib

      hello guys, i have a problem here ....
      i'm trying  to enter this command " show ip route " on ISP & R1 routers , but i cant see the Bgp routes in the table .
      so how can i configure it , and to make the Clients to ping the server "209.65.200.241".

      the lab is attached.


      Regards,
      Sohaib

        • 1. Re: Bgp problem
          Sey

          Hey Sohaib,

           

          Not everyone is so lucky to have Packet Tracer. It's not freeware you know. So more people could help you if you posted a screenshot of your topology and config files in plain text.

          • 2. Re: Bgp problem
            Daz_UK

            Hi Sohaib

             

            First regarding BGP config on ISP router you had the wrong mask configured in your BGP Network statement . It does not match what is configured on the interface Fast 0/0 .

             

            Also ISP has no knowledge of the internal network past R1 . You could redistribute your OSPF routes into BGP ?

            • 3. Re: Bgp problem
              Nuno

              hi Sohaib, please post the configs instead of packet tracer files.

               

              your edge router must have a static route to ISP and the ISP to the edge router should also have a static route.

              second, are you running an IGP in your lan? BGP routes should first be learned via IGP, also depending on the IOS simulation that packet tracer uses, if im not mistaken, before 12.2(?T) you should use the no synchronization command.

              • 4. Re: Bgp problem
                Sohaib

                hello guys ,
                here is my topolgy and its configs .


                thanks 

                • 5. Re: Bgp problem
                  Sey

                  Note that you're not advertising the subnet leading to Server0. Also, in your situation the following command does not make much sense as you have a BGP neighbor on that same link only:

                   

                  network 209.65.200.224 mask 255.255.255.252

                  • 6. Re: Bgp problem
                    Sohaib

                    so , what shall i do here ?!!

                    • 7. Re: Bgp problem
                      Sey

                      You want server0 to be reachable, so you have to advertise it via some routing protocol or a static route. You have only BGP on ISP router, and you want BGP to be doing something useful. On ISP try adding

                       

                      router bgp 65002

                      no network 209.65.200.224 mask 255.255.255.252

                      network 209.65.200.240 mask 255.255.255.248

                      end

                      • 8. Re: Bgp problem
                        Sohaib

                        it doesnt work ,

                        • 9. Re: Bgp problem
                          Sey

                          If it does not work, something must be wrong. You as a network engineer can troubleshoot it. Are all participating interfaces in Up/Up state? Can ISP and R1 ping each other? Is there a BGP neighborship between them? Post output from both R1 and ISP:

                           

                          show ip bgp summary

                          show ip protocols

                          show ip route

                          show ip bgp

                          • 10. Re: Bgp problem
                            Brian

                            You need to advertise the network on R1 to the ISP so he knows how to direct the packets back.  Or since you have a static default route, just send R1 the default route via BGP.  Here is what you should have on the ISP router under BGP.

                             

                            ISP

                            router bgp 65002

                            bgp log-neighbor-changes

                            no synchronization

                            neighbor 209.65.200.225 remote-as 65001

                            neighbor 209.65.200.225 default-originate

                            network 209.65.200.240 mask 255.255.255.248

                             

                            Since you are already redistributing the BGP route (default only) into OSPF, this should be advertised to all other OSPF routers.

                             

                            Brian