I'd like to request a way to have a customizable response message that a daemon returns, much like the way Postfix allows you to specify an error number and “message”.
The concept is based on my other request of having some level of user account status. The assumption is that some business logic would be:
Customer has not paid this month, their account is locked so they cannot read their Email, but we want people to still be able to send to them.
So if I have set a users status to “Locked non-payment”, then when they go to POP their account the error response would say, “POP not allowed due to non-payment”. This way a user would know the exact problem rather than just the standard message saying that the account doesn't exist. At the same time they may still receive messages via LMTP/SMTP.
This may be implementable via the new ACL method in 2.1.7, but I have not had the ability to test that feature.
Regardless of the ability to set status, it might be nice to customize the response messages for branding purposes. Plus I had one customer become highly offended by one of the current POP message responses due to bad password.