So I have an exercise with this topology: [![enter image description here][1]][1] I have configured all the OSPF networks on each router and I made every g0/0 interface (except for the ABR in the middle) a passive interface. However, I cannot ping from PC11 to PC1 (or any other PC in another area). Here are the configurations of the routers: **R1** : interface GigabitEthernet0/0 ip address 192.168.1.1 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 ip address 192.168.99.1 255.255.255.0 duplex auto speed auto ! interface Vlan1 no ip address shutdown ! router ospf 1 log-adjacency-changes passive-interface GigabitEthernet0/0 network 192.168.2.0 0.0.0.255 area 0 network 192.168.3.0 0.0.0.255 area 0 network 192.168.1.0 0.0.0.255 area 0 network 192.168.99.0 0.0.0.255 area 0 ! ip classless **R2** : interface GigabitEthernet0/0 ip address 192.168.2.1 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 ip address 192.168.99.2 255.255.255.0 duplex auto speed auto ! interface Vlan1 no ip address shutdown ! router ospf 1 log-adjacency-changes passive-interface GigabitEthernet0/0 network 192.168.3.0 0.0.0.255 area 0 network 192.168.1.0 0.0.0.255 area 0 network 192.168.99.0 0.0.0.255 area 0 network 192.168.2.0 0.0.0.255 area 0 ! ip classless **R3** : interface GigabitEthernet0/0 ip address 192.168.3.1 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 ip address 192.168.99.3 255.255.255.0 duplex auto speed auto ! interface Vlan1 no ip address shutdown ! router ospf 1 log-adjacency-changes passive-interface GigabitEthernet0/0 network 192.168.2.0 0.0.0.255 area 0 network 192.168.1.0 0.0.0.255 area 0 network 192.168.99.0 0.0.0.255 area 0 network 192.168.3.0 0.0.0.255 area 0 ! ip classless **ABR :** interface GigabitEthernet0/0 ip address 192.168.99.4 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 ip address 172.16.99.4 255.255.255.0 duplex auto speed auto ! interface Vlan1 no ip address shutdown ! router ospf 1 log-adjacency-changes network 192.168.99.0 0.0.0.255 area 0 network 172.16.99.0 0.0.0.255 area 2 **R11 :** interface GigabitEthernet0/0 ip address 172.16.1.1 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 ip address 172.16.99.1 255.255.255.0 duplex auto speed auto ! interface Vlan1 no ip address shutdown ! router ospf 1 log-adjacency-changes passive-interface GigabitEthernet0/0 network 172.16.2.0 0.0.0.255 area 2 network 172.16.3.0 0.0.0.255 area 2 network 172.16.1.0 0.0.0.255 area 2 network 172.16.99.0 0.0.0.255 area 2 **R12 :** interface GigabitEthernet0/0 ip address 172.16.2.1 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 ip address 172.16.99.2 255.255.255.0 duplex auto speed auto ! interface Vlan1 no ip address shutdown ! router ospf 1 log-adjacency-changes passive-interface GigabitEthernet0/0 network 172.16.1.0 0.0.0.255 area 2 network 172.16.3.0 0.0.0.255 area 2 network 172.16.99.0 0.0.0.255 area 2 network 172.16.2.0 0.0.0.255 area 2 **R13 :** interface GigabitEthernet0/0 ip address 172.16.3.1 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 ip address 172.16.99.3 255.255.255.0 duplex auto speed auto ! interface Vlan1 no ip address shutdown ! router ospf 1 log-adjacency-changes passive-interface GigabitEthernet0/0 network 172.16.1.0 0.0.0.255 area 2 network 172.16.2.0 0.0.0.255 area 2 network 172.16.99.0 0.0.0.255 area 2 network 172.16.3.0 0.0.0.255 area 2 As you can see in the routing table; PC11 only knows the devices in his area...is that normal? Shouldn't it also know the devices in the other area? What am I missing here? Thanks in advance. [1]: https://i.sstatic.net/NXVpF.png