I've set up a Postfix/Courier mail server that is not quite mission-critical, but still quite a critical system.
Does anyone know of any systems I can use to thoroughly test the system for any errors - I dont really know how to go about testing it from the perspective of another user.
I want to test whether the system will receive various different emails from various different users, not just the odd test account I use.
As long as the other users are equally set up like the "odd test account" then you are done. You components should make no difference between users who are set up the exact same way.
What you need to check before you go productive with your system is if it is a danger for the public (the outside world). Check it with MXtoolbox and abuse.net if it is an open relay. If yes, then close it now!
The same tests should be applied for SPF and DKIM *) whereas they are no danger for the public but increase your deliverability reputation.
*) mail to [email protected]