Our mail server at work is still getting attacked by a rumplestiltskin attack and after looking at the whois information it’s the same guy as last time so I think a polite email to abuse and firstname.lastname@example.org and @comtech-data.se may pay dividends.
Meanwhile, I found a good article on stopping spam with open source software. I must roll some of those Sendmail m4 directives into Install-Sendmail soon.
From the maillog:
May 5 04:10:43 mail sendmail: g453Agr08030: ... User unknown
May 5 04:10:44 mail sendmail: g453Agr08030: from=, size=0, class=0, nrcpts=0, proto=SMTP, daemon=MTA, relay=rlkal1a046.comtech-data.se [18.104.22.168] (may be forged)