Hmmm... thanks everybody.
Tom, that's exactly what I did. I thought that qmail was still running, but it actually wasn't. I temporarily closed down port 25 through iptables (lokkit). The queue had over 40.000 emails in it. I found an instruction on google on how to delete them. Basically you can delete them manually but shouldn't delete folders.
Then I added all my domains to accepted domains (rcpthosts), which I must have deleted incidently. By the way: What is the difference of rcpthosts and locals? Should all domains be in both files or only in rcpthosts?
