SPAM, Postfix security

    I got a little question!!


    I regionized that i got a lot of "Automatic Reply" Messages around the Christmas days! Some mails got me my original Message in the reply message! Okay it just says "merry Christmas" as text and ":-)" as subject nothing else.


    It was send from a phantasy name, and phantasy mailbox name but with my original Domainname...!


    Now i checked my Postfix configuration on the server and saw this information:


    It's quite possible that the emails and log entries are not related, but should both be issues for concern, so I would check them out in detail.


    The 'SASL LOGIN authentication failed' might be a would-be attacker (or a sucessful one) trying to guess your password. If there are many of these such entries, it could be a 'dictionary attack', where the person tries your username with a password from a list (eg 'password', 'a', 'aa', 'aaa', or 'Adam', 'Bob', 'Carry' and so on).


    Look into installing fail2ban on your server. This will help to trace this in real time and place a ban on the incoming IP address after a certain number of tries.


    The 'setting up TLS connection' probably means there was a correct guess. Maybe reset your password to something a bit stronger.


    However, if it appears you have been hacked, it might be a good idea to reset accounts and re-install items. I would suggest a proper end-to-end check of the system.