IP Routing Protocols

SECURITY CONSIDERATIONS

OSPF implements security operations to prevent unauthorized routers and other masquerading nodes from doing damage to a routing domain. The OSPF router can be configured to support simple password authentication in clear text, or secret key authentication, typically with the MD5 operation.

The idea of MD5 for OSPF is to make it very difficult for an attacker to generate a phony OSPF packet that would be accepted by a routing domain. A hash value is computed to authenticate the packet and MD5 is designed to prevent an attacker from appending a phony hash value to the packet. If the attacker tries to do so, the receiving router's calculations reveals that the hash value in not valid, and rejects the packet.