Okay, I had the occasional SPAM message hitting my inbox, like every 1 out of 10 e-mails. But over the last couple of weeks that ratio seemed to flip. I had to do something in order to take back control; take some time for it now in order to save some time in the future. Since I don't believe in filtering in the inbox (or server based filtering of content for that matter), it had to be a solution at the receiving end of the server. Also, blocking at the receiver alerts the sender of a false positive that the e-mail they send will not be read (non-delivery error) which on the long run is far less intrusive to communication than silently dropping the false positive.
Building on past experience as systems administrator (I'm talking about the year 2003 now), we had about 97% of all incoming mails being either SPAM or addressed to no-existing mailboxes. For e-mail security we used MIMEsweeper, but it first received the mail (receiver service) and then processed it according its policies (security service). This way of working was both overloading the server and producing silent false positives (not many, but still). In order to fight SPAM more efficiently and be able to better spot false positives, we needed a solution capable of denying access to the server... and we found just the product to do that: Open Relay Filter by Vamsoft. This enabled to both block blacklisted servers at the door and reject mail for non-existing recipients, and instead of having to add another mail-gateway to support the overloaded server, utilization levels of the mail-gateway dropped to an acceptable level.
About 2 years back, Vamsoft invited MCT's to sign up for ORF for free, I jumped on the offer and today that offer really helped me out!!! Installation and configuration on my Small Business Server just toke a few minutes (about 25% of time compared to blogging about it).