About the SMTP relay
Email relays are typically used by larger organizations to distribute a high volume of mail to several internal mail servers. You can use the SMTP relay for this purpose. You can configure separate SMTP relays for incoming and outgoing email. Before you can configure the SMTP relay, you must configure your Smoothwall to allow traffic through to the relay.
Non-standard SMTP checks
Non-standard SMTP checking checks email that doesn't adhere to the SMTP message format and contains badly formatted or bogus information about the sender and recipient.
External email relay
All outbound email is attempted to be delivered directly to the appropriate server by default. You can relay all outgoing email to another mail relay.
Antimalware with the SMTP Relay
You can scan relayed email for malware and take appropriate action as specified by the antimalware settings configured.