To configure additional BGP options – CLI

config router bgp

set bestpath-med-missing-as-worst enable set fast-external-failover enable

set graceful-restart enable set graceful-restart-time 120 set graceful-stalepath-time 180 set graceful-update-delay 180 set holdtime-timer 120

set keepalive-timer 45

set log-neighbor-changes enable config neighbor

edit 172.21.111.4

set connect-timer 60 set description “ISP1” set holdtime-timer 120 set keepalive-timer 45 set weight 250

next

edit 172.22.222.4

set connect-timer 60 set description “ISP2” set holdtime-timer 120 set keepalive-timer 45 set weight 100

next end

end

 

Configuring other networking devices

There are two other networking devices that need to be configured: both ISPs’ BGP routers.

The ISPs’ routers must add the FortiGate unit as a neighbor so route updates can be sent in both directions. Note that ISP1 is not directly connected to ISP2 that we are aware of.

Inform both of your ISPs of your FortiGate unit’s BGP information. Once they have configured their router, you can test your BGP connection to the Internet.

They will require your FortiGate unit’s:

• IP address of the connected interface
• The router ID
• Your Company’s AS number

Testing this configuration

With the dual-homed BGP configuration in place, you should be able to send and receive traffic, send and receive routes, and not have any routing loops. Testing the networks will confirm things are working as expected.

In general for routing you need to look at the routing table on different routers to see what routes are being installed. You also need to sniff packets to see how traffic is being routed in real time. These two sources of information will normally tell you what you need to know.

Testing of this example’s network configuration should be completed in two parts:

• Testing network connectivity
• Verifying the FortiGate unit’s routing tables
• Verifying traffic routing
• Verifying the dual-homed side of the configuration

Testing network connectivity

A common first step in testing a new network topology is to test if you can reach the Internet and other locations as you expect you should. If not, you may be prevented be cabling issues, software or other issues.

The easiest way to test connections is to use ping, once you ensure that all the FortiGate unit’s interfaces and ISP routers have ping support enabled. Also ensure that the security policies allow ping through the firewall.

Connections to test in this example are the internal network to ISP1’s router or the Internet, and the same for ISP2. If you can connect on the external side of the Fortinet unit, try to ping the internal network. Those three tests should prove your basic network connections are working.

Once you have completed testing the network connectivity, turn off ping support on the external interfaces for additional security.

 

Verifying the FortiGate unit’s routing tables

The FortiGate routing table contains the routes stored for future use. If you are expecting certain routes to be there and they are not, that is a good indicator that your configuration is not what you expected.

The CLI command get router info routing-table details will provide you with every route’s routing protocol, destination address, gateway address, interface, weighting, and if the address is directly connected or not.

If you want to limit the display to BGP routes only, use the CLI command get router info routing- table bgp. If there are no BGP routes in the routing table, nothing will be displayed. In the CLI command you can replace BGP with static, or other routing protocols to only display those routes.

If you want to see the contents of the routing information database (RIB), use the CLI command get router info routing-table database. This will display the incoming routes that may or may not make it into the routing table.