saracen,

There are two cases where connections are dropped even if the IP is in the whitelist.

1. The greylist filter. IPs will be subjected to greylisting even if they are present in the whitelist. There is a separate method of adding IPs to an exception to prevent them from being stopped by this filter (http://www.logsat.com/spamfilter/Forums/forum_posts.asp?TID=6379)

2. The "IP blacklist cache". If an IP has been sending spam during the last few minutes, it will be temporarily blocked at a TCP level, regardless of the IP whitelist.

It is to be noted however that in #2 above, if the IP is whitelisted, it won't be blocked by the other filters, so the email should never end up in the blacklist cache to begin with...

For the greylist in #1, greylisting very, very rarely will block legitimate IP. The (again very rare) times this happens, it is usually caused by the remote server having many different IP addresses which are used to send emails, not just one.

All this said, if you can please zip and email us at support at logsat.com SpamFilter's activity logfile for a day this happened, we'll take a look. Please also include the sender's IP address in question.

If the zip is over 5MB in size, please use our FTP site to upload the file. I'll send you the FTP login info in a PM.