An L4 server is installed. The LB algorithm can be anything (hash/sticky bit), defined at the Real server level.
Persistence (sticky) sessions are enabled on the L4 server. You usually define this at the virtual server level.
SSL VPN servers are installed and imported into the same administration console. The health status of all the imported servers must be green or yellow.
The traffic policies must be imported into the SSL VPN servers before they are clustered.
An SSL VPN Server configuration is created for the cluster, and all the SSL VPN servers are assigned to this configuration.
The base URL DNS name of this configuration must be the virtual IP address of the L4 server. The L4 balances the load between the SSL VPN servers in the cluster.
The following ports are open on the L4 server for SSL VPN communication:
8080 (for HTTP communication)
8443 (for HTTPS communication)
7777 (for Stunnel over TCP and OpenVPN over UDP)
7778 (for OpenVPN over TCP)