Does my machine send spam???

Mon Oct 17 06:21:58 UTC 2016

Hi!

I've got six messages, which say, that some spam message can't be delivered. 
I've attached one of them.

I've had attacks on my local Dovecot mail server, but they should have been 
blocked by fail2ban - ?.

Has my machine been hijacked to send spam?? What can I do?

Greetings
Volker
-------------- next part --------------
An embedded message was scrubbed...
From: Mail Delivery System <Mailer-Daemon at belogorsk.net>
Subject: Mail delivery failed: returning message to sender
Date: Mon, 17 Oct 2016 10:51:18 +0900
Size: 5008
URL: <https://lists.ubuntu.com/archives/ubuntu-users/attachments/20161017/a66dd4bd/attachment.mht>