In the hopes that relating my experience with spamd will motivate some people to contribute to this bounty, and ultimately motivate a developer to take the bounty, here is the story.
I have put up a FreeBSD 7.x box where I want the pfSense box(es) to see how much of a difference spamd is going to make. So far, it looks like it is going to knock about half the load off my Barracuda boxes.
I moved one unit behind the spamd box yesterday and saw a drop in message attempts per hour on that box drop from 18,000 per hour to about 3,000 per hour.
I left it running that way for about 20 hours and it worked it's way up to about 4,000 per hour for the hour before I began moving the second barracuda.
Servers were not being very successful in un-greylisting themselves because when box 1 told them to shove off, they immediately sent the message via box 2. At 11am I disabled the second box. In a couple of hours, we were seeing about 8,300 message attempts per hour on the protected box. The number of whitelisted entries climbed very quickly. (Before the spamd box was inline, one box could not have survived handling the e-mail load by itself. It ran about 2 hours 50 minutes taking the full load without breaking a sweat.)
We now have both boxes behind the spamd box and are seeing just under 6,000 message attempts per hour per box. The number of allowed messages per hour per box has gone from about 2,000 to about 1,000. If things stay this way, my customers are going to start wondering where their spam is. So far, we have had no complaints of missing e-mail. However, we are only 25 hours in. I suspect more and more spam hosts will successfully white list themselves, but the Barracudas should take care of them when they get through. I have hope that we will stabilize at around 10,000 message send attempts per hour per box. That will be an almost 50% reduction in load on the barracudas. This is a very impressive layer to add to the e-mail security onion.
The spamd box is a Via C7 1GHz with 256MB RAM and 3 Intel gigabit NICs. I still have about 20MB free memory and we are at about 20% cpu utilization system wide. The spamd processes themselves are using about 17% of the CPU.
All of that to say, having spamd working on a pfSense box could very well save your spam scanning hardware from needing to be upgraded for a year or two. I spent 2 weeks trying to get the pfSense development environment figured out and finally punted and had the raw FreeBSD solution up in about a day with configuring everything by hand.
Getting someone to make this all clickable in pfSense will be very much worth the money I have pledged to the bounty. I sure hope someone takes my money. They will have earned it.