Is it me John Wayne, is it you?

Some spammers can really drive you mad - especially if they are doing things like that. Looking at my mailserver logs I have found some strange IP addresses like 123.27.3.81, 222.252.80.188 or 123.16.13.188 which are resolving to ‘localhost’ regarding to their reverse DNS. In other words, a bad configured mailserver thinks that the mail comes from itself and offers special treatment to that messages - which usually means they bypass the spamfilter. The problem can be solved quite simple by using ‘127.0.0.1’ instead of ‘localhost’ in your configuration files and you got green conditions again.