SonicWall Email Security How to setup Round Robin or Fail-over

How to setup Email Security to use Round Robin or Fail-over when there is more than one downstream server.

1. Login to email security as "Admin"
2. Go to Manage | System Setup | Network | Server Configuration
3. Edit the current inbound path if there is one; or add new path.
4. Pull down the side bar to number 3. Destination of Path

Here there are two options one is:

• This is a Proxy. Route email in Round-Robin or Failover mode to the following multiple destination servers [Its faster but never queues emails for delivery later]
• This is an MTA. Route email using SmartHost in Round-Robin or Failover mode to the following multiple destination servers

If Round robin is specified, email will be load-balanced by sending a portion of the email flow through each of the servers specified in the text box in round-robin order. All of the servers will process email all the time. 

If Fail over is specified, the first server listed will handle all email processing under normal operation. If the first server cannot be reached, email will be routed through the second server. If the second server cannot be reached, email will be routed through the third server, and so on. 

These choices enable queuing, so if all of the specified downstream hosts are unavailable for any reason, email will be queued and will retry transmission later.