07-30-2013 01:23 PM - edited 03-04-2019 08:36 PM
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?
07-31-2013 03:07 AM
Ignore last, I'm going blind! Please post 'sh ip int br' and 'sh ip route ospf' again.
07-31-2013 03:18 AM
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
07-31-2013 03:23 AM
Try adding 'redistribute connected' to both of your 'router ospf 1' instances.
07-31-2013 03:22 AM
if its any help I've done no setup on the backbone for vlans...
07-31-2013 03:24 AM
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.
07-31-2013 03:33 AM
That sounds the problem....
How would I correct that setup?
07-31-2013 03:35 AM
Try adding 'redistribute connected' to both of your 'router ospf 1' instances.
07-31-2013 03:39 AM
I've added this and the ping from both PC's still fails...
07-31-2013 03:45 AM
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
!
07-31-2013 03:55 AM
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?
07-31-2013 04:05 AM
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.
07-31-2013 04:40 AM
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
!
07-31-2013 06:35 AM
I think, there could be a subnetting issue. Can you confirm, have you configured proper subnetmask(Routers/PC's) in your devices.
07-31-2013 02:43 PM
Have you checked if the two routers are OSPF neighbors on the fa0/0 interfaces?
show ip ospf neighbor
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