Defining your pool of back-end servers

Before FortiADC can distribute connection requests from clients, it must first know the IP addresses of your servers. To define your server farm, first define the methods that FortiADC use to monitor each server for availability (see “Monitoring your servers’ responsiveness”), then go to Server Load Balance > Resources > Pool.

When adding each back-end server in the pool definition, you can define separate connection limits that FortiADC uses while a server is not yet ready to handle full capacity (a “warm-up rate”), such as while returning online again after the health check monitor detected downtime.

For example, if this network service is brought up before other daemons have finished initializing, and therefore the server’s CPU and memory are more utilized than they will be after startup is complete, you would define a separate warm-up rate and/or recovery rate. During scheduled maintenance, you can also manually apply these limits by setting Status to Maintenance instead of Enable. The SSL to Server option allows you to specify whether FortiADC connects to the back-end server using SSL or TLS. (Sometimes this is called “re-encryption” because FortiADC terminates and decrypts the connection on the client side.) For details, see “How to re-encrypt SSL/TLS to back-end servers”.

The Backup Server option allows you to specify a server that FortiADC directs traffic to only when other servers in the pool are down.

If you use Layer 7 session persistence with a back-end server, FortiADC will inject an HTTP cookie whose name you can configure in Cookie. This contains the FortiADC session ID and will enable the appliance to forward subsequent related requests to the same back-end server.


	To prevent session tampering, use a web application firewall such as FortiWeb. Failure to do so could compromise the continuity of sessions and allow attackers to hijack other clients’ sessions. While the FortiADC session cookie is only used for routing, many web applications also use session cookies which are more sensitive, such as for authentication.