routing problem across multiple routers

[bradholman]

I am migrating our network to a new metro-Ethernet provider, and at the same time changing our LAN subnet (because we are currently using a non-private subnet for our LAN). I have our current network on 192.47.0.0/16 using router1. I have configured a new hub router2 using 192.168.100/24, and a 'bridge' router between the two. Here is a diagram of my current configuration.

Router1 is running RIP, Router2, Router3, and Bridge are running OSPF. My situation is that while I can ping from router1 all hops through to a client on the 192.168.11.0/24 subnet, I cannot ping from router3 to router1 (the traffic gets to the bridge router then stops).

Here is the routing table for router1:

Gateway of last resort is 192.47.100.32 to network 0.0.0.0

     192.168.72.0/32 is subnetted, 1 subnets
S       192.168.72.45 [1/0] via 192.47.100.32
S    192.47.30.0/24 [1/0] via 192.47.100.32
R    192.47.8.0/24 [120/1] via 10.1.4.254, 00:00:22, GigabitEthernet0/1.4
S    192.47.110.0/24 [1/0] via 192.47.100.32
R    192.47.9.0/24 [120/1] via 10.1.3.254, 00:00:18, GigabitEthernet0/1.3
R    192.47.10.0/24 [120/1] via 10.1.6.254, 00:00:23, GigabitEthernet0/1.6
     172.16.0.0/32 is subnetted, 1 subnets
S       172.16.209.21 [1/0] via 192.47.100.32
S    192.168.11.0/24 [1/0] via 192.47.100.9
R    192.47.11.0/24 [120/1] via 10.1.7.254, 00:00:12, GigabitEthernet0/1.7
R    192.47.4.0/24 [120/1] via 10.1.5.254, 00:00:22, GigabitEthernet0/1.5
S    192.47.21.0/24 [1/0] via 192.47.100.32
S    192.47.20.0/24 [1/0] via 192.47.100.32
R    192.47.5.0/24 [120/1] via 10.1.1.254, 00:00:03, GigabitEthernet0/1.1
R    192.47.6.0/24 [120/1] via 10.1.2.254, 00:00:17, GigabitEthernet0/1.2
     10.0.0.0/8 is variably subnetted, 9 subnets, 2 masks
C       10.1.3.0/24 is directly connected, GigabitEthernet0/1.3
C       10.1.2.0/24 is directly connected, GigabitEthernet0/1.2
C       10.1.1.0/24 is directly connected, GigabitEthernet0/1.1
C       10.1.7.0/24 is directly connected, GigabitEthernet0/1.7
C       10.1.6.0/24 is directly connected, GigabitEthernet0/1.6
C       10.1.5.0/24 is directly connected, GigabitEthernet0/1.5
C       10.1.4.0/24 is directly connected, GigabitEthernet0/1.4
S       10.1.254.168/32 [1/0] via 192.47.100.31
S       10.48.239.0/24 [1/0] via 192.47.100.32
S    192.47.1.0/24 [1/0] via 192.47.100.32
S    192.47.2.0/24 [1/0] via 192.47.100.31
C    192.47.100.0/24 is directly connected, GigabitEthernet0/0
S    192.168.100.0/24 [1/0] via 192.47.100.9
S*   0.0.0.0/0 [1/0] via 192.47.100.32

Here is the routing table for bridge:

Gateway of last resort is 192.168.100.3 to network 0.0.0.0

O    192.168.11.0/24 [110/3] via 192.168.100.1, 04:06:27, GigabitEthernet0/1
     10.0.0.0/24 is subnetted, 2 subnets
O       10.0.10.0 [110/2] via 192.168.100.1, 04:06:27, GigabitEthernet0/1
O       10.0.11.0 [110/2] via 192.168.100.1, 04:06:27, GigabitEthernet0/1
C    192.47.100.0/24 is directly connected, GigabitEthernet0/0 Shouldnt this forward the traffic for me?
C    192.168.100.0/24 is directly connected, GigabitEthernet0/1
S*   0.0.0.0/0 [1/0] via 192.168.100.3
S    192.47.0.0/16 [1/0] via 192.47.100.10

Here is the routing table for router2:

Gateway of last resort is 192.168.100.2 to network 0.0.0.0

O    192.168.11.0/24 [110/2] via 10.0.11.254, 04:23:37, GigabitEthernet0/1.11
     10.0.0.0/24 is subnetted, 2 subnets
C       10.0.10.0 is directly connected, GigabitEthernet0/1.10
C       10.0.11.0 is directly connected, GigabitEthernet0/1.11
C    192.168.100.0/24 is directly connected, GigabitEthernet0/0
S*   0.0.0.0/0 [1/0] via 192.168.100.2

Here is the routing table for router3:

Gateway of last resort is 192.168.100.1 to network 0.0.0.0

C    192.168.11.0/24 is directly connected, GigabitEthernet0/1
     10.0.0.0/24 is subnetted, 2 subnets
O       10.0.10.0 [110/2] via 10.0.11.1, 04:11:32, GigabitEthernet0/0.11
C       10.0.11.0 is directly connected, GigabitEthernet0/0.11
O    192.168.100.0/24 [110/2] via 10.0.11.1, 04:11:32, GigabitEthernet0/0.11
S*   0.0.0.0/0 [1/0] via 192.168.100.1

In summary, pinging router1 from router3 does not work, but pinging router3 from router1 does. Any help is appreciated, thanks!

Brad

[Seb Rupik]

Hi Brad,

What does the <router ospf> configuration look like on router2?

cheers,

Seb.

[Jon Marshall · Accepted solution]

Brad

When you ping from router 3 the source IP address will be 10.0.11.254.

But router 1 has no route for that subnet so it cannot send return packets.

So you need to add a route to router 1 for router 3's 10.0.11.0/24 subnet.

Alternatively you could configure mutual redistribution between OSPF and RIP if you wanted.

Edit - I know you said you could ping all the hops from router 1 to router 3 but I am not sure how as there is no route in the routing table for that subnet.

Jon