Example Weighted load balancing configuration

This example shows how to using firewall load balancing to load balances all traffic among 3 real servers. In the example the Internet is connected to port2 and the virtual IP address of the virtual server is 192.168.20.20. The load balancing method is weighted. The IP addresses of the real servers are 10.10.10.1, 10.10.10.2, and 10.10.10.3. The weights for the real servers are 1, 2, and 3.

This configuration does not include a health check monitor.

GUI configuration

Use the following procedures to configure this load balancing setup from the FortiGate GUI.

To add the HTTP virtual server

1. Go to Policy & Objects > Virtual Servers.
2. Select Create New.
3. Add an IP virtual server that allows users on the Internet to connect to the real servers on the internal network. In this example, the FortiGate port2 interface is connected to the Internet.

Name	HTTP_weghted_LB
Type	IP
Interface	port2
Virtual Server IP	192.168.20.20
Load Balance Method	Weighted

All other virtual server settings are not required or cannot be changed.

4. Under Real Servers select Create New.
5. Add three real servers. Because the Load Balancing Method is Weighted, each real server includes a weight. Servers with a higher weight receive a more sessions.
   Configuration for the first real server.

IP Address	10.10.10.1
Weight	1
Max Connections	0 Setting Max Connections to 0 means the FortiGate unit does not limit the number of connections to the real server.
Mode	Active

Configuration for the second real server.

IP Address	10.10.10.2
Weight	2
Max Connections	0
Mode	Active

Configuration for the third real server.

IP Address	10.10.10.3
Weight	3
Max Connections	0
Mode	Active

To add the virtual server to a security policy

Add a port2 to port1 security policy that uses the virtual server so that when users on the Internet attempt to connect to the web server’s IP address, packets pass through the FortiGate unit from the wan1 interface to the dmz1 interface. The virtual IP translates the destination address of these packets from the virtual server IP address to the real server IP addresses.

1. Go to Policy & Objects > IPv4 Policy.
2. Select Create New.
3. Configure the security policy:

Name	Policy name
Incoming Interface	port2
Outgoing Interface	port1
Source	all (or a more specific address)
Destination	HTTP_weghted_LB
Schedule	always
Service	ALL
Action	ACCEPT
NAT	Select this option and select Use Destination Interface Address.

4. Select other security policy options as required.
5. Select OK.

CLI configuration

Load balancing is configured from the CLI using the config firewall vip command and by setting type to server-load-balance. The default weight is 1 and does not have to be changed for the first real server.

Use the following command to add the virtual server and the three weighted real servers.

config firewall vip

edit HTTP_weghted_LB

set type server-load-balance

set server-type ip

set extintf port2

set extip 192.168.20.20

set ldb-method weighted

config realservers

edit 1

set ip 10.10.10.1

next

edit 2

set ip 10.10.10.2

set weight 2

next

edit 3

set ip 10.10.10.3

set weight 3

end

end