Sending Mail

To restrict which email addresses a user can send messages to, edit the user (in the Users page), and in the permissions tab for the user, leave the 'Allow sending of Internet Mail' box checked but and the email addresses you want to allow into the 'Target Whitelist' setting. If you want to allow sending to all addresses except a few, then put the blocked addresses in the 'Target Blacklist' setting. The procedure VPOP3 uses is: * Is Outgoing mail allowed - if so, block the message * Is ...

In the SMTP protocol, a blank sender email address has a special meaning. It means that you do not want to receive bounce messages. This is useful with automated messages. For instance, you do not want to receive bounce messages in response to another bounce message - or you could end up with a loop with two mail servers endlessly sending messages back and forth to each other. Similarly, receiving bounce messages to autoresponse messages etc is also generally undesirable. In these cases, the Sta...

The method for sending different users' mail using multiple Mail Senders (https://helpdesk.pscs.co.uk/687781-Sending-different-users-mail-through-different-ISP-relay-accounts) in VPOP3 works well for up to 10 ISP relay accounts, but cannot be used for more than that, and can become cumbersome before that. _The method listed below requires VPOP3 7.0 or later_, but may be easier to use if you have many ISP relay accounts. Note that it is still probably easier to use an SMTP relay service which al...

If you are using VPOP3 7.0 or later, there is an alternative method (https://helpdesk.pscs.co.uk/387819-Sending-different-users-mail-separately-using-MX-DNS-Overrides) to that shown below. Occasionally people need to send mail from different users through different ISPs or through ISP accounts with different authentication details. In most cases this is not necessary, because most business ISPs will accept mail from any email address as long as they authenticate properly, however if your ISP i...