Fortigate BGP (Border Gateway Protocol) configuration is a technique commonly used to manage network traffic and ensure proper routing of external network connections. BGP is crucial in large networks and Internet Service Provider (ISP) connections. This article will explain step-by-step how to configure BGP on Fortigate devices.

What is BGP?

BGP is a routing protocol that manages routing between multiple networks. It is most commonly used between Internet Service Providers and large networks. BGP ensures the correct delivery of IP packets by selecting the best path in the routing table. It plays a key role in the internet's backbone by sharing routing information across different networks.

Configuring BGP on Fortigate Devices

Fortigate devices are security appliances that support BGP and are highly effective in routing traffic within a network. To configure BGP on Fortigate, several key steps must be followed.

1. Enabling BGP

Before using BGP on a Fortigate device, the BGP feature must be enabled. This can be done by following these steps:

1. Login to the Fortigate device.

2. Enable BGP through the CLI (Command Line Interface).

In this configuration, represents the AS number of the network, and Router-ID is the ID of the device, which is typically its IP address or a static address.

2. Configuring BGP Interfaces

BGP typically operates between two routers, so it is essential to configure the physical or virtual interfaces that connect them. The configuration for these interfaces is as follows:

This configuration will allow the Fortigate device to start exchanging BGP information with the neighboring router by specifying its IP address and AS number.

3. Adding a BGP Prefix List

It is important to define which IP prefixes will be routed via BGP. This can be done on Fortigate as follows:

By specifying a particular IP block (prefix), you can ensure that traffic for this network is routed via BGP.

4. Adding BGP Routing Filters

Sometimes, certain routes need to be blocked or modified. Fortigate allows the use of filters for such scenarios. Filters control the BGP information the router receives and sends.

This filter checks incoming and outgoing BGP traffic through specified interfaces.

5. Checking BGP Status

To verify if BGP is configured correctly, the following command can be used on the Fortigate device:

This command will display the status of active BGP peers and show which routers have successfully established connections and which have encountered issues.

6. Viewing the BGP Routing Table

The BGP routing table shows the paths selected by the router. To view the table, use the following command:

This command provides a list of active BGP routes and shows the best paths used by the router.

7. Adding and Managing BGP Routing Information

Fortigate devices provide dynamic routing through BGP. However, sometimes you may want to prioritize certain routes. For route management, Fortigate devices offer path selection options like AS-path, prefix-length, and MED (Multi-Exit Discriminator).

8. BGP Security Settings

Since BGP communicates with external networks, it is essential to apply security measures. Fortigate devices offer several ways to secure BGP communications:

• BGP Authentication: To secure BGP communication, both peers can sign BGP messages.

• Route Filtering: You can filter out certain routes to prevent routing for specific IP blocks.

9. BGP Failover and Redundancy Configuration

Fortigate devices support the use of redundant connections with BGP. This ensures that if one link fails, traffic is rerouted via another path. The dynamic nature of BGP helps ensure the network operates without interruption, even during failures.

Conclusion

Configuring BGP on Fortigate devices is an important aspect of network management. BGP allows for efficient routing and sharing of routing information between different networks. In this article, we covered the basic steps for configuring BGP on Fortigate devices, but remember that every network has different requirements, so customization may be necessary. Fortigate offers strong security features and flexible configuration options that enable efficient management of network traffic.