Link Load Balancing : Configuring health check rules
 
Configuring health check rules
Link health checks test routes to the specified destination. When the link health check option is enabled for a gateway link, the system periodically sends an ICMP ECHO probe (ping) to a beacon—an IP address that must be reachable in order for the link to be deemed available. A beacon can be any IP address, such as a main office, core router, or virtual server at another data center.
Before you begin:
• You must have knowledge of a destination IP address that can function as a beacon for the health check.
• You must have Read-Write permission for Link Load Balance settings.
After you have configured a health check, you can select it in the gateway link configuration.
To configure a health check:
1. Go to Link Load Balance > Link Group.
2. Click the Health Check tab.
3. Click Add to display the configuration editor.
4. Complete the configuration and add members as described in Table 19.
5. Save the configuration.
Table 19: Link policy health check configuration
Settings
Guidelines
Name
Unique name. No spaces or special characters.
After you initially save the configuration, you cannot edit the name.
Interval
The default is 5. The default is recommended in most cases.
Retry
The default is 3. The default is recommended in most cases.
Timeout
The default is 3. The default is recommended in most cases.
Source IP Address
Source IP address specified in the health check packet header.
You do not necessarily need to configure the source address of the health check or its individual probes unless you want it to differ from the network interface IP address, or differ from the source IP used by other probes in the health check.
The probe’s source IP address is configurable at multiple levels. The system uses the most specific source address that you configure for each probe:
• If a source IP address is configured for the health check member, the system uses that source address as the SRC field in the packet’s IP header.
• If source IP address for the health check member remains at its default value (0.0.0.0) but you have configured an health check group source IP address, the system uses that address.
• If both group and member settings are not configured (remaining at their default value of 0.0.0.0), the system uses the IP address of the network interface from which the packet is sent.
The default is 0.0.0.0.
Check Member
Name
Unique name. No spaces or special characters.
After you initially save the configuration, you cannot edit the name.
Address
You must specify a destination IP address.
When the link health check option is enabled within an active link group, the system periodically sends an ICMP ECHO probe (ping) to a beacon—an IP address that must be reachable in order for the link to be deemed available. A beacon can be any IP address, such as a main office, core router, or virtual server at another data center.
Source IP Address
Source IP address specified in the health check packet header.
You do not necessarily need to configure the source address of the health check or its individual probes unless you want it to differ from the network interface IP address, or differ from the source IP used by other probes in the health check.
The probe’s source IP address is configurable at multiple levels. The system uses the most specific source address that you configure for each probe:
• If a source IP address is configured for the health check member, the system uses that source address as the SRC field in the packet’s IP header.
• If source IP address for the health check member remains at its default value (0.0.0.0) but you have configured an health check group source IP address, the system uses that address.
• If both group and member settings are not configured (remaining at their default value of 0.0.0.0), the system uses the IP address of the network interface from which the packet is sent.
The default is 0.0.0.0.