I’m working on IPExpert section 16. I’ve been working on it for days. Im making good progress today but have run into an OSPF deal that has me a little stumped. First off here is a little clip of the topology:
Now here is the config from the routers:
R2:
interface Serial0/1/0
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
frame-relay lmi-type cisco
!
interface Serial0/1/0.4 point-to-point
ip address 192.1.24.2 255.255.255.0
ip access-group IDS_s0/1/0.4_in_0 in
frame-relay interface-dlci 104
!
interface Serial0/1/0.5 point-to-point
ip address 192.1.25.2 255.255.255.0
ip access-group IDS_s0/1/0.5_in_0 in
frame-relay interface-dlci 105
!
interface Serial0/1/0.6 point-to-point
ip address 192.1.26.2 255.255.255.0
frame-relay interface-dlci 106
!
interface Serial0/2/0
no ip address
shutdown
clock rate 2000000
!
interface FastEthernet1/0
no switchport
ip address 192.1.12.2 255.255.255.0
!
!
router ospf 1
router-id 2.2.2.2
log-adjacency-changes
area 10 virtual-link 4.4.4.4
network 2.2.2.2 0.0.0.0 area 0
network 192.1.12.0 0.0.0.255 area 0
network 192.1.24.0 0.0.0.255 area 10
network 192.1.25.0 0.0.0.255 area 0
network 192.1.26.0 0.0.0.255 area 10
!
ip classless
!R5:
interface Serial0/1/0
ip address 192.1.25.5 255.255.255.0
encapsulation frame-relay
ip ospf network point-to-point
frame-relay map ip 192.1.25.2 501 broadcast
no frame-relay inverse-arp
frame-relay lmi-type cisco
!
interface Serial0/2/0
no ip address
shutdown
!
router eigrp 100
redistribute ospf 1 metric 1 1 1 1 1
network 10.5.5.0 0.0.0.255
no auto-summary
!
router ospf 1
router-id 5.5.5.5
log-adjacency-changes
redistribute eigrp 100 metric 120 subnets
network 5.5.5.5 0.0.0.0 area 0
network 192.1.25.0 0.0.0.255 area 0
network 200.1.1.6 0.0.0.0 area 0
!
ip classless
!
!
ip http serverR4:
interface Serial0/0/0
ip address 192.1.24.4 255.255.255.0
encapsulation frame-relay
ip ospf network point-to-point
frame-relay map ip 192.1.24.2 401 broadcast
no frame-relay inverse-arp
frame-relay lmi-type cisco
!
router ospf 1
router-id 4.4.4.4
no log-adjacency-changes
area 10 virtual-link 2.2.2.2
network 4.4.4.4 0.0.0.0 area 10
network 192.1.24.0 0.0.0.255 area 10
network 192.1.49.0 0.0.0.255 area 10
!
ip classless
!
!
ip http server
no ip http secure-serverR6:
!
interface Serial0/1/0
ip address 192.1.26.6 255.255.255.0
encapsulation frame-relay
ip ospf network point-to-point
--More--
frame-relay map ip 192.1.26.2 601 broadcast
no frame-relay inverse-arp
frame-relay lmi-type cisco
!
interface Serial0/2/0
no ip address
shutdown
clock rate 2000000
!
interface Serial0/2/1
no ip address
shutdown
clock rate 2000000
!
router ospf 1
router-id 6.6.6.6
log-adjacency-changes
redistribute rip metric 120 subnets
network 6.6.6.6 0.0.0.0 area 10
network 192.1.6.0 0.0.0.255 area 10
network 192.1.26.0 0.0.0.255 area 10
!
router rip
version 2
redistribute ospf 1 metric 5
network 172.16.0.0
no auto-summary
!
ip classless
!
!
no ip http server
no ip http secure-server
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
exec-timeout 0 0
line aux 0
line vty 0 4
login
!
warm-reboot
scheduler allocate 20000 1000
!
end*Oct 10 18:18:53.238: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 192.1.25.5, S 
I just labbed this up myself so I can be certain before I responded.
The configuration you displayed is correct and is working. Did you copy and paste this into your lab devices? The only think I can think of is I typed out your config by establishing OSPF adjacencies first and then adding the virtual-links to R2 and R4.
Virtual-links are quirky at times. You may want to remove them and then re-add them back to see if the error goes away. Otherwise, post up some debugs.
The configs here are copied right off the gear. What I should have done, and I’ve done in the past, is simply reboot R5. After I did that the issue cleared itself. Ugh.