Prasanth
The network statement used under an IGP configuration such as OSPF/EIGRP tells the router which interfaces to start running the routing protocol on. So
router ospf 1
network 192.168.5.0 0.0.0.255 area 0
this tells the router to start OSPF running on any interface that has an address within the 192.168.5.x subnet range. So if the router had an interface
int fa0/0
ip address 192.168.5.1 255.255.255.0
then OSPF would be run on that interface. Note that the network command for an IGP like OSPF/EIGRP does not tell the router which networks to advertise. (It does however for BGP).
0.0.0.0 255.255.255.255 matches anything so
router ospf 1
network 0.0.0.0 255.255.255.255 area 40
tells the router to start OSPF up on all interfaces on the router and that they are all in area 40 which is unusual but not impossible if that is the only area you have.
Jon
