Never react to an e-mail that asks for your password\!

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A few days ago one of our users replied to an e-mail that apparently was sent by “support” and asked for username and password. This account was later misused to send hundred thousands spam-mails through our mail server. This resulted in the blacklisting of our outgoing mail server in e.g. the blacklists of Windows Live Hotmail. The fastest way to remedy this is to give our outgoing mail server a different IP-address, which we did this morning. Lesson: Never reply to an e-mail that asks for your username and password! It causes a lot of trouble for us and other users.