spam

Rodney Tillotson The expectation that e-mail services will return a failure notice or report for messages that cannot be delivered is no longer realistic. In most cases Janet-connected organisations should not attempt to provide such notifications.

If your mailer has been an open relay for some time, and particularly if it has been used by spammers, it may well be on one or more blacklists. The blacklists are a very important co-operative activity of the anti-spam community. Certain organisations or individuals maintain lists of IP addresses or address ranges and make them available in ways which enable users of the lists to reject attempted mail transfers from those addresses. Once your mailer is working properly you should check with all the lists you know and request removal if necessary.

Much of the required behaviour can be achieved by configuring your mail software. The details vary considerably between products and you should consult the product documentation or present your requirements very carefully to any contractors managing your mailers. It is unfortunate that in many cases the default behaviour (the way the software works as delivered or following a standard installation, upgrade or patch) is to openly relay, so you should check after making any changes.