Currently, there is still a good amount of Spam getting through Spam Filter ISP when compared to other solutions we've had in place.

Over the course of a day I will get 15-20 messages that are spam in my inbox while only 2-4 show up in my quarantine. I know that more is getting disconnected based on being from foreign addresses, etc. but more is getting through than what we experienced with previous solutions. For example, with a competing product I would get2-4 messages per week in my inbox.

Also, I'm finding that clients of ours are having their emails rejected by the spam filter unless they are added to the domain-to-domain whitelist. Yet, nothing in the content once it's received is indicative of spam (they get an NDR that states that there was a spam signature embedded in the message).

Additionally, our clients that we have going through the filter also report the same things, that companies sending email to them get rejected unless defined in the domain-to-domain filter yet they continue to receive emails that are clearly and unquestionably spam in their inboxes.

One of the things we love about the product is that it drops connections from most sources limiting the bandwidth being used, but it's frustrating to our clients that mail that is clearly spam gets through while legitimate email is rejected unless the domain is whitelisted.

Any thoughts as to why this is happening?

saracen,

Most likely this is either caused by a misconfiguration in SpamFilter, or it is due to the fact that SpamFilter is not seeing the "real" IP address of the sender (this happens if you have another server process the emails before they reach SpamFilter, or if your firewall masks the IPs from the internet when NAT'ting them). If you can please zip and email us (support at logsat dot com) about one hour worth of logs from SpamFilter's activity logfile, along with the SpamFilter.ini file, and you let us know what version of SpamFilter you're using, we'll try to help.
Please also include the various text files containing your configuration files, especially the one containing the list of your local domains.

saracen, just my 2 cents worth:

LogSat,

Thanks LogSat.  I made some changes earlier today to my MAPS and SURBL lists, as well as updated my DNS servers and they seem to be catching emails now.