If an attacker gains access to your network, they can masquerade as a router on your network to either gain information about your network or disrupt network traffic. If you have a high quality firewall configured, it will help your network security and stop many of this type of threat. However, the main method for protecting your routing information is to use authentication in your routing protocol. Using authentication on your FortiGate unit and other routers prevents access by attackers — all routers must authenticate with passwords, such as MD5 hash passwords, to ensure they are legitimate routers.

When configuring authentication on your network, ensure you configure it the same on all devices on the network. Failure to do so will create errors and outages as those forgotten devices fail to connect to the rest of the network.

For example, to configure an MD5 key of 123 on an OSPF interface called ospf_test, enter the following CLI command: