We have used limesurvey to send invitations and confirmations. It is not a seeding, we sent 400 emails to people who we knew their name, family name and email address. Email was personalized with "Dear Mr. [Name]".
"IP Address XX.XXX.XXX.XXX is listed in the CBL. It appears to be infected with a spam sending trojan, proxy or some other form of botnet.
It was last detected at 2013-XX-XX 02:00 GMT (+/- 30 minutes), approximately 6 hours ago.
This IP address is HELO'ing as "localhost.localdomain" which violates the relevant standards (specifically: RFC5321).
The CBL does not list for RFC violations per-se. This _particular_ behaviour, however, correlates strongly to spambot infections. In other words, out of thousands upon thousands of IP addresses HELO'ing this way, all but a handful are infected and spewing junk. Even if it isn't an infection, it's a misconfiguration that should be fixed, because many spam filtering mechanisms operate with the same rules, and it's best to fix it regardless of whether the CBL notices it or not."