Mail Flow

The Mail Flow section displays the following information:

Directory services synchronization:A warning alert is triggered if there is one instance (or as many as five instances) of the following synchronization failures:

  • recipient aliases
  • groups
  • recipient validation

A critical alert is triggered if there are six or more failures.

Delivery message queue: A warning alert is triggered if the Email Appliance is having difficulty delivering messages. A critical alert is issued if it is extremely difficult for the appliance to deliver messages. This can occur if the Email Appliance is generating a high number of internal messages or if an external mail server becomes unavailable.

Mandatory TLS domains: (This is only displayed if TLS encryption is enabled.) A warning alert is triggered if the appliance fails to establish a TLS connection for a domain where TLS is required.

Pre-filter message queue: A warning alert is triggered if there is a high number of messages that have yet to be processed. A critical alert is issued if there is an extremely high number of unprocessed messages. This may be due to excessive mail traffic or an issue with the mail filter.

SMTP connections: A critical alert is issued if your appliance has reached its maximum number of connections on port 25. This could result in delays in message processing. It may be the result of excessive mail traffic, or an issue with the mail filter. This condition is often caused by a sudden increase in SMTP connections due to typical day-to-day spikes, or potentially denial-of-service attacks. If this condition persists, consider adding another Sophos Email Appliance to deal with the increased traffic.

SPX encryption: (This is only displayed if SPX encryption is enabled.) A critical alert is issued if there is an error while generating an encrypted PDF. The message is moved to the failed queue, and Sophos Technical Support is notified.

SPX encryption queue: A warning alert is triggered if the number of unprocessed messages in the system is high. A critical alert is issued if the number of unprocessed messages reaches the maximum level. This is either because the password store is unavailable, or the appliance is unable to process messages at a sufficient rate that require encryption .

SPX password service: (This is only displayed if SPX encryption is enabled, and at least some message recipients have the ability to choose their own password.) A failure alert is triggered if there is an error performing SPX password service. A separate alert is issued if the password service is disabled.