In order for F5 load balancing to be configured properly, the Virtual IP address (VIP) of the LTM server must be set as the loopback interface on DNS/DHCP Servers in the F5 pool.
If there's more than one VIP associated with an LTM server, all of those IP addresses must be set as loopback addresses on the DNS/DHCP Servers in the F5 pool.
The VIP of the LTM server must be obtained when configuring the LTM server on the F5 management interface. For more information, refer to https://f5.com/products/big-ip/local-traffic-manager-ltm.
To configure loopback addresses:
- From the configuration drop-down menu, select a configuration.
- Select the Servers tab. Tabs remember the page you last worked on, so select the tab again to ensure you're on the Configuration information page.
- Click the server or xHA pair name menu button and select Service Configuration.
- From the Service Type drop-down menu, select Interfaces. Address Manager queries the server and returns the current interface configurations.
- Under the Interface column, choose the loopback (lo) interface then navigate across the row to the Action column and click Edit. The Edit Interface pop-up window opens.
Complete the following:
- In the Description field, enter a name for the new loopback address. You can enter up to 80 alphanumeric characters including spaces, but excluding special characters.
- In the Address/CIDR field, enter the VIP of the
LTM server using CIDR notation. For example, 192.0.2.100/32. This
will be the loopback address assigned to the Service interface of the
DNS/DHCP Server.Note: Only a /32 is a valid CIDR value for loopback addresses.
- Click Add Address. The loopback address appears in the Addresses list. Add additional loopback addresses as needed. To delete an address, select a loopback address from the Addresses list and click Remove.
- Click OK.
- Under Addresses, expand to view the newly added loopback address.