exim DDOS "Sender verify failed" in debian7

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Posted by ediaz, 03-27-2014, 12:53 PM
Hi to all this is my system. Debian 7.4 last version This server was running like 4 years. In pass time like 3 days ago I get a log of messages of this. I put fail2ban to ban all the robots, but I don't understand why me :-).. I have now like 1000 machines banned from my system adycoaduanas:/var/log/exim4# shorewall show | grep DROP | wc 1002 9103 89634 this is a attack of DDOS? how I can prevent this attack? This is my config for exim. Any idea because I have like 10 servers very similar in the configuration and this no happens with others. Regards for you time.
Posted by hostabit, 04-11-2014, 10:35 AM
It is quite common if you have 'Sender verify' turned on. The amount mostly depend how much domains you have on a server and how popular/old the domains are. For domains that have existed a long time, spammers are trying to send spam to every existing and non-existing account.