1

If two router are connected through a serial link, they form neighborship even if they belong from different network.

I configured 1st router with IP 10.1.1.1/8 and 2nd with 10.1.1.2/16 and they formed neighborship. Why it happened so??

2
  • this is not an enterprise networking question therefore off-topic
    – marctxk
    Nov 24 '16 at 10:17
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 15 '17 at 5:29
3

10.1.1.0/16 is a subnet of 10.1.1.0/8.

Both of your routers are in the network 10.1.1.0/16 so it is normal that they form a neighbor relationship.

You should fix your addressing.

1

OSPF hellos do not use the subnet address, they use multicast so they will be received by each router. I guess this should be off-topic since it's not an entreprise networking question.

1

OSPF does not require neighbors to be on the same IP network if the network type is point-to-point. An adjacency will form even if the interfaces are unnumbered. In this case, they are both on the 10.1/16 network though.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.