Routing problem in BGP network

[Gideon Goddard]

Hello,

I'm making a BGP network with 3 AS. I use 6 routers 3725.

I've making my routers configuration by reading these two links :

http://www.cisco.com/cisco/web/support/CA/fr/109/1094/1094968_bgp-toc.html

http://www.cisco.com/cisco/web/support/CA/fr/109/1093/1093302_23.html

Here is my topology.

Here is R5 configuration :

conf t

 hostname R5

 !---configuration physical interface

 interface fastEthernet 0/0
  ip addr 20.0.4.2 255.255.255.252
  no shutdown
  exit

 interface fastEthernet 1/0
  ip addr 192.168.5.253 255.255.255.0
  no shutdown
  exit

 ip routing

 !--- configuration eBGP link

 router bgp 500
  neighbor 20.0.4.1 remote-as 300
  exit

 !---configuration iBGP link

 router bgp 500
  neighbor 192.168.5.254 remote-as 500
  exit

All router are configured in the same way.

My problem is, for exemple with my W7 I can't go out of my LAN ...

Where am I wrong ??

thanks

[Ganesh Hariharan]

what is the ip address of W7 and i see the port is showing red on diagram.

-GI

[Gideon Goddard]

192.168.1.1

It is marked in red because it is not turn on. But W7 pings it LAN as well as Kali & Ubuntu computer 

By LAN I mean 192.168.1.0/24 and 20.0.2.1 because 192.168.1.254 is it default gateway.

[naresh tikader]

have u even have any outside network in your routing table  , 

R1#sh ip route

     20.0.0.0/30 is subnetted, 1 subnets
C       20.0.6.0 is directly connected, FastEthernet0/0
C    192.168.1.0/24 is directly connected, FastEthernet1/0

u should have  routes for wan networks  in routing table to reach them advertise them with network command under router bgp AS no. 

[Abzal]

Hi,

Can R1 and R2 see other subnets except own subnets? Do they see BGP neighbors R6, R3?

[Gideon Goddard]

R1#sh ip route

     20.0.0.0/30 is subnetted, 1 subnets
C       20.0.6.0 is directly connected, FastEthernet0/0
C    192.168.1.0/24 is directly connected, FastEthernet1/0

R1#sh ip bgp summary
BGP router identifier 192.168.1.253, local AS number 100
BGP table version is 1, main routing table version 1

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
20.0.6.2        4   500       6       7        1    0    0 00:03:50        0
192.168.1.254   4   100       7       7        1    0    0 00:04:26        0

R2#sh ip route
     20.0.0.0/30 is subnetted, 1 subnets
C       20.0.2.0 is directly connected, FastEthernet0/0
C    192.168.1.0/24 is directly connected, FastEthernet1/0

R2#sh ip bgp summary
BGP router identifier 192.168.1.254, local AS number 100
BGP table version is 1, main routing table version 1

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
20.0.2.2        4   300       8       8        1    0    0 00:05:16        0
192.168.1.253   4   100       8       8        1    0    0 00:05:24        0

I don't use any loopback interface to configure bgp, I would do it as simple as possible.

I think the problem is I don't see  BGP route in my sh ip route command ... But why ??

EDIT : I think it a problem on my iBGP links because eBGP seems to work no ?

Here is a capture on f0/0 of R2.

Here is a capture on f1/0 of R2

So it the forwarding from iBGP toward eBGP which doesn't work ?

[Ganesh Hariharan]

Hello ,

Lets do step by step by having neighbour ship between R1 and R6.

First are you able to ping the router interfaces , I hope yes.

Then create a eBGP neighbour ship between the two and advertise network and see are you able to see those network in routing table or not.

once done then create a igbo between R1 and R2 and you are seeing the routes in R2 table or not.

-GI

[Gideon Goddard]

Yes I can ping the router interface in my LAN with W7 for exemple.

How do I advertise network ? I thought it was making in an automatic way...

Do I have to advertise eBGP network, iBGP netowrk or both ?

[Ganesh Hariharan]

Hello,

For exterior protocols the network command controls which networks are advertised.So from R1 under ebgp configuration 

From R1 point of view ..configure the below

router bgp 100
  neighbour R6 ip address remote-as 500
  network 192.168.1.0 255.255.255.0
neighbour R2 ip address remote-as 100

and see in at R6 routing table are you able to see subnet advertise from R1 or not (192.168.1.0/24)

-GI

[paul driver]

Hello

On your  ebgp/Ibgp routers  apply the next hop-self command facing the Ibgp peers as taking r5 as an example it will be advertising updates to R4  for sw3 as a next hop of 192.168.5.2 and not  192.168.5.1 . Also I don't see ibgp peering between r5 and r6 to establish a full Ibgp mesh

Lasty make sure R6/SW3/R5 have full connectivity to each other using either static routing or some igp (rip/eigrp/ospf)  to negate the sychronisation rule

res

paul