Delivering Outbound Messages Via Clustered Slaves

Starting v7.6, administrators can relay outbound messages through configured slaves in a clustered environment. This feature provides redundancy for outbound email delivery. Consider the following scenario as an example:

  • A user sends an outbound email to This message is initially sent to the MASTER Xeams.
  • If the first delivery attempt fails, message is sent to one of the configured slaves. Communication between MASTER and SLAVE is done via HTTP(S) rather than SMTP.

Configuring Xeams

  • This option is turned on by default
  • To turn it off, go to Server Configuration, SMTP Configuration, select the Advanced tab and uncheck Relay Thru Clustered Slaves

Confirming Message Delivery Through Slaves

Following methods confirm if a message went out through a slave.

  • The color for Status Icon for email delivery will turn Blue
  • The host name will start with "slave:" in OutboundAuditTrailSuccess.log

Emails That Are NOT Routed Through Slaves

  • Inbound or Internet emails
  • Original recipient belongs to a distribution list
  • Smart host is used or the domain exists in hosts.txt file