Spam Prevention using Postscreen

From now on we are using postscreen as the first defense against incoming spam. That means all incoming SMTP connections must pass a SMTP greeting check and checks against zen.spamhaus.org as well as b.barracudacentral.org. Should an incoming connection fail to successfully complete both checks incoming mail will not be accepted.

Anyone using the Webmailer running on mail.roath.org should not experience any difficulties with the new setup, but smaller amounts of spam.

Anyone using a Mailclient that used to use mail.roath.org:25 for outgoing mail should switch that to mail.roath.org:587. The submission port is not protected by postscreen, but authentication is mandatory in order to deliver mail over this port.