BGP Configuration on FortiOS
I’ve never done a post on Forti-anything, but I’m really appreciating the products Fortinet is putting out lately. They’re transitioning from “run your SMB off of our stuff” to “actually, we’re pretty good for larger companies”, so their GUI lacks features to keep the SMB from blowing stuff up, The advanced features are there in the CLI, and I wanted to use it to show that difference between the GUI and the real config.
Let’s review some of the basic configuration elements of BGP first. You need an autonomous system (AS) number and a router ID for your side. You also need the AS number of the remote system. You need the IP address on their side (usually the interface facing you). That looks something like this. We’re going to be ‘Fortigate 1’ for this exercise.

With just this information, we can turn up a BGP neighbor that does absolutely nothing. To actually send some routes, you need to tell BGP what to send. We’ll keep this simple and add just connected networks. Adding to the diagram, we get this.

Now we have something of value (though choosing BGP over OSPF or RIP for this little scenario is pretty horrible). Continue reading