Basic load balancing configuration example

This section describes the steps required to configure the load balancing configuration shown below. In this configuration a FortiGate-51B unit is load balancing HTTP traffic from the Internet to three HTTP servers on the Internal network. HTTP sessions are accepted at the wan1 interface with destination IP address 172.20.120.121 on TCP port 8080 and forwarded from the internal interface to the web servers. When forwarded the destination address of the sessions is translated to the IP address of one of the web servers.

The load balancing configuration also includes session persistence using HTTP cookies, round-robin load balancing, and TCP health monitoring for the real servers. Ping health monitoring consists of the FortiGate unit using ICMP ping to make sure the web servers can respond to network traffic.

To configure the example load balancing configuration – general configuration steps

1. Add a load balance ping health check monitor.

A ping health check monitor causes the FortiGate unit to ping the real servers every 10 seconds. If one of the servers does not respond within 2 seconds, the FortiGate unit will retry the ping 3 times before assuming that the HTTP server is not responding.

2. Add a load balance virtual server.

3. Add the three load balance real servers. Include the virtual server in each real server configuration.

4. Add a security policy that includes the load balance virtual server as the destination address.

 

To configure the example load balancing configuration – web-based manager

1. Go to Policy & Objects > Health Check and add the following health check monitor.

Name                                           Ping-mon-1

Type                                            Ping

Interval                                       10 seconds

Timeout                                      2 seconds

Retry                                           3

2. Go to Policy & Objects > Virtual Servers and add virtual server that accepts the traffic to be load balanced.

Name                                           Vserver-HTTP-1

Type                                            HTTP

Interface                                     wan1

Virtual Server IP                        172.20.120.121

Virtual Server Port                    8080

Load Balance Method              Round Robin

Persistence                                HTTP Cookie

HTTP Multiplexing                    Do not select

Health Check                             Move Ping-mon-1 to the Selected list.

3. Go to Policy & Objects > Real Servers and add the real servers.

Virtual Server                             Vserver-HTTP-1

IP Address                                 10.31.101.30

Port                                             80

Weight                                        n/a

Max Connections                      0

Mode                                           Active

Virtual Server                             Vserver-HTTP-1

IP Address                                 10.31.101.40

Port                                             80

Weight                                        n/a

Max Connections                      0

Mode                                           Active

Virtual Server                             Vserver-HTTP-1

IP Address                                 10.31.101.50

Port                                             80

Weight                                        n/a

Max Connections                      0

Mode                                           Active

4. Go to Policy & Objects > IPv4 Policy and add a wan1 to internal security policy that includes the virtual server.

This policy also applies an Antivirus profile to the load balanced sessions.

 

	Incoming Interface	wan1
	Source Address	all
	Outgoing Interface	internal
	Destination Address	Vserver-HTTP-1
	Schedule	always
	Service	ALL
	Action	ACCEPT
	NAT	Turn on NAT and select Use Destination Interface Address.
	Antivirus	Turn ON and select an Antivirus profile.
5.	Select OK.

 

To configure the example load balancing configuration- CLI

1. Use the following command to add a Ping health check monitor.

config firewall ldb-monitor edit ping-mon-l

set type ping set interval 10 set timeout 2 set retry 3

end

2. Use the following command to add the virtual server that accepts HTTP sessions on port 8080 at the wan1 interface and load balances the traffic to three real servers.

config firewall vip edit Vserver-HTTP-1

set type server-load-balance set server-type http

set ldb-method round-robin set extip 172.20.120.30

end

set extintf wan1 set extport 8080

set persistence http-cookie set monitor tcp-mon-1

config realservers edit 1

set ip 10.31.101.30 set port 80

next edit 2

set ip 10.31.101.40 set port 80

end

3. Use the following command to add a security policy that includes the load balance virtual server as the destination address.

config firewall policy edit 0

set srcintf wan1 set srcaddr all

set dstintf internal

set dstaddr Vserver-HTTP-1 set action accept

set schedule always set service ALL

set nat enable

set utm-status enable

set profile-protocol-options default set av-profile scan

end