Vlan over Routers & Switches - Page 2

iangillbanks · ‎07-30-2013

Hello,

I'm trying to solve a packet tracer problem but I'm running out of ideas and could do with some suggestions/help.

I have the following setup

1 switch as the backbone, which is linked to 4 routers linked to individual switches. From here each switch is connect to a computer each on a different VLAN. So for example 1 switch is connected to a computer on Vlan 2 then Vlan 3 and Vlan 4. The second switch is also connected to 3 computers again 1 on Vlan 2, another Vlan 3 and then Vlan 4. Finally the routers are WAN connected to each other. Hope that paints the picture.

Router 1 & 2 can ping each other over the WAN connection

The routers have trunking setup for each Vlan

If I ping from a PC on Vlan 2 to another PC on the same Vlan the ping fails. The packet leaves the PC, goes through the switch and into the router then the packet is dropped. The packet doesn’t go through the WAN connection.

I’ve ran out of ideas on what to check or change to either route the packet over the WAN of through the backbone?

Any ideas?

Seb Rupik · ‎07-31-2013

Ignore last, I'm going blind! Please post 'sh ip int br' and 'sh ip route ospf' again.

iangillbanks · ‎07-31-2013

Maybe this could be a problem.... "sh ip route ospf" doesn't show anything... but below is my show running-config output

Router 1

router ospf 1

log-adjacency-changes

passive-interface FastEthernet0/1

network 50.25.220.0 0.0.0.7 area 0

Router 2

router ospf 1

log-adjacency-changes

passive-interface FastEthernet0/1

network 50.25.220.0 0.0.0.7 area 0

Router 1

Interface IP-Address

FastEthernet0/0 50.25.220.1

FastEthernet0/1 unassigned

FastEthernet0/1.2 50.25.0.1

FastEthernet0/1.3 50.25.0.129

FastEthernet0/1.4 50.25.1.1

Serial0/0/0 50.25.221.1

Router 2

Interface IP-Address

FastEthernet0/0 50.25.220.2

FastEthernet0/1 unassigned

FastEthernet0/1.2 50.25.1.129

FastEthernet0/1.3 50.25.2.1

FastEthernet0/1.4 50.25.2.129

Serial0/0/0 50.25.221.2

Seb Rupik · ‎07-31-2013

Try adding 'redistribute connected' to both of your 'router ospf 1' instances.

iangillbanks · ‎07-31-2013

if its any help I've done no setup on the backbone for vlans...

Seb Rupik · ‎07-31-2013

It would appear your routers are connected to the backbone on VLAN1 (default). Since you can ping the routers form eachother, we know that IP transport is working fine between them.

It is just the routers not knowing what routes the other router provides which is the problem.

iangillbanks · ‎07-31-2013

That sounds the problem....

How would I correct that setup?

Seb Rupik · ‎07-31-2013

Try adding 'redistribute connected' to both of your 'router ospf 1' instances.

iangillbanks · ‎07-31-2013

I've added this and the ping from both PC's still fails...

Seb Rupik · ‎07-31-2013

OK try:

Router1

!

router ospf 1

log-adjacency-changes

passive-interface FastEthernet0/1

redistribute connected subnets

network 50.25.220.0 0.0.0.7 area 0

network 50.25.0.0 0.0.0.128 area 0

network 50.25.0.128 0.0.0.128 area 0

network 50.25.1.0 0.0.0.128 area 0

!

Router2

!

router ospf 1

log-adjacency-changes

passive-interface FastEthernet0/1

redistribute connected subnets

network 50.25.220.0 0.0.0.7 area 0

network 50.25.1.128 0.0.0.128 area 0

network 50.25.2.0 0.0.0.128 area 0

network 50.25.2.128 0.0.0.128 area 0

!

iangillbanks · ‎07-31-2013

I thought that might have been it... but I got this error message

OSPF: Invalid address/mask combination (discontiguous mask)

Is there no setup needed for the backbone to carry the VLAN settings?

Seb Rupik · ‎07-31-2013

OK try normal subnet masks:

Router1

!

router ospf 1

log-adjacency-changes

passive-interface FastEthernet0/1

redistribute connected subnets

network 50.25.220.0 0.0.0.7 area 0

network 50.25.0.0 255.255.255.128 area 0

network 50.25.0.128 255.255.255.128 area 0

network 50.25.1.0 255.255.255.128 area 0

!

Router2

!

router ospf 1

log-adjacency-changes

passive-interface FastEthernet0/1

redistribute connected subnets

network 50.25.220.0 0.0.0.7 area 0

network 50.25.1.128 255.255.255..128 area 0

network 50.25.2.0 255.255.255.128 area 0

network 50.25.2.128 255.255.255.128 area 0

!

Nope, the VLAN config to the backbone should remain as it is.

Seb Rupik · ‎07-31-2013

Depending on IOS verisons you may not be able to use netmasks, so try the following wildcards:

Router1

!

router ospf 1

log-adjacency-changes

passive-interface FastEthernet0/1

redistribute connected subnets

network 50.25.220.0 0.0.0.7 area 0

network 50.25.0.0 0.0.0.255 area 0

network 50.25.1.0 0.0.0.127 area 0

!

Router2

!

router ospf 1

log-adjacency-changes

passive-interface FastEthernet0/1

redistribute connected subnets

network 50.25.220.0 0.0.0.7 area 0

network 50.25.1.128 0.0.0.127 area 0

network 50.25.2.0 0.0.0.255 area 0

!

karthikgiri1984 · ‎07-31-2013

I think, there could be a subnetting issue. Can you confirm, have you configured proper subnetmask(Routers/PC's) in your devices.

james.doukas · ‎07-31-2013

Have you checked if the two routers are OSPF neighbors on the fa0/0 interfaces?

show ip ospf neighbor