/ IMAP List Administration wrote on Tue 13.Nov'12 at 21:55:11 +0100 / > [example of delivery failure] > Nov 13 15:10:29 dna prefilter/smtpd[9340]: connect from unknown[8.7.42.206]
I've been getting client requests from this ip as well, i've put it into a permenant spamd(8) blacklist.