Link Load Balancing : Configuring persistence rules
 
Configuring persistence rules
Persistence rules identify traffic that should be ignored by load balancing rules and instead be forwarded to the same gateway each time the traffic traverses the FortiADC appliance.
You should use persistence rules with applications that use a secure connection. Such applications drop connections when the server detects a change in a client’s source IP address.
Table 27 describes the types of persistence rules you can configure.
Table 27: Persistence rules used in link load balancing
Persistence
Description
Source-Destination Pair
Packets with the same source IP address and destination IP address take same outgoing gateway.
Source-Destination Address
Packets with a source IP address and destination IP address that belong to the same subnet take the same outgoing gateway.
Source Address
Packets with a source IP address that belongs to the same subnet take the same outgoing gateway.
Destination Address
Packets with a destination IP address that belongs to the same subnet take same outgoing gateway.
Before you begin:
• You must have an awareness of the types of outbound traffic from your network. Persistence rules are useful for traffic that requires an established session, such as secure connections (HTTPS and SSH, for example).
• You must have knowledge of the source and/or destination subnets to which the persistence rules should apply.
• You must have Read-Write permission for Link Load Balance settings.
 
You can use persistence rules in link groups but not virtual tunnels.
To configure a persistence rule:
1. Go to Link Load Balance > Link Group.
2. Click the Persistence tab.
3. Click Add to display the configuration editor.
4. Complete the configuration as described in Table 28.
5. Save the configuration.
Table 28: Persistence rule configuration
Type
Guidelines
Name
Configuration name. Valid characters are A-Z, a-z, 0-9, _, and -. No spaces. You reference this name in the link group configuration.
Note: After you initially save the configuration, you cannot edit the name.
Source-Destination Pair
Timeout
The default is 300 seconds.
Source Address
Timeout
The default is 300 seconds.
Source IPv4 Maskbits
Number of bits in a subnet mask to specify a network segment that should following the persistence rule.
For example, if you set this to 24, and the system chooses a particular gateway router for client IP 192.168.1.100, the system will select that same gateway for subsequent client requests when the subsequent client belongs to subnet 192.168.1.0/24.
Source-Destination Address
Timeout
The default is 300 seconds.
Source IPv4 Netmask Bits
Number of bits in a subnet mask to specify a network segment that should following the persistence rule.
Destination IPv4 Netmask Bits
Number of bits in a subnet mask to specify a network segment that should following the persistence rule.
For example, if you set this to 24, and the system chooses a particular gateway router for destination IP 192.168.1.100, the system will select that same gateway for traffic to all destination IPs in subnet 192.168.1.0/24.
Destination Address
Timeout
The default is 300 seconds.
Destination IPv4 Netmask Bits
Number of bits in a subnet mask to specify a network segment that should following the persistence rule.