Core migration routing issue - Cisco to Juniper and the Smoothwall

[dazza007]

Ok so I am trying to do the what feels like the impossible migrate cisco core to juniper all live.

I have been through the internet and support routes and I thought I had solved the issue but realised I had a return routing problem!!

 

The Cisco core is connected with an interlink trunk and standby ips on the vlan with a gateway to the smoothwall.

 

The plan which I thought was working was to transfer the vlan ip from the cisco and change L3 on the Cisco vlan to L2.

 

I hit a problem where the Smoothwall would return the traffic to the second core instead of the first core. The return IP address on the Smoothwall would be the standby shared IP of the vlan on the cores.

This caused a bootloop because the route on the second core states 0.0.0.0/0 go to core 1 (mgmt ip) so traffic went back and forth to the smoothwall. The traffic would go to core 2 even if originating from core 1, smoothwall conclude it is not their issue.

 

Adjusting the gateway (next-hop) of the vlan on the smoothwall to go to ip address of the smothwall vlan on the juniper fixed this and adding routes to the cores allowed traffic .

 

This will all work if the vlan concerned was not on migrated off the cisco as the routes entered send the traffic to the Juniper, so clients on the network

 

If you are asking why I am doing this (because I am too! ) then the lead times of network equipment throws the best laid plans under the bus, which is where I am at.

 

However the clients in the vlan connected on the cisco don't get return traffic as the routes entered for the vlan say to go to the juniper switch..

 

The network is all static routes

Edited May 11, 2023 by dazza007

[Davit2005]

Are you on the smoothwall pointing the route for a bigger subnet or jus moving one subnet at a time to the Juniper?

 

What you might be able to do is give a lower route metric to the ones you are moving off to the Juniper so they get routed correctly?

Edited May 11, 2023 by Davit2005