Problem :- Router R1 is advertising all of its network(s) in OSPF area 0. Router R2 is advertising E0/0 IP network 10.1.1.0/30 in OSPF area 0, E1/0 network 188.8.131.52/30 in EIGRP AS 100. R3 is advertising all three networks in EIGRP 100.
Redistribution is done from EIGRP AS 100 to OSPF Process Id 10 ( area 0) and vice versa.
Redistribution commands used as below
redistribute eigrp 100 metric 555 ( Configured under router ospf 10 )
redistribute ospf 10 metric 10000 100 255 1 1500 ( Configured under router eigrp 100)
From R1 I am not able to ping 184.108.40.206 but I am able to ping 220.127.116.11 . Why? What is wrong in redistribution.
Solution :- when we redistribute networks in OSPF then we need to use a keyword “subnets” at the end of the command. So configuration should have been as below
redistribute eigrp 100 metric 555 subnets ( Configured under router ospf 10 )
If we don’t use the keyword “subnets” then redistribution will only happen for classful networks. That’s the reason that ping is working for 18.104.22.168 because it has subnet mask of 255.255.0.0 i.e. /16 and 140 also belongs to Class B Range. Therefore, it is classful.
While 22.214.171.124/29 is part of 126.96.36.199/29 network and it is a classless i.e. network which is divided or subnetted.
Moreover, if we miss the keyword “subnets” while in redistribution then below message will generate
R2(config-router)#router os 10
R2(config-router)#redistribute eigrp 100 metric 555
% Only classful networks will be redistributed