I have pfsense 1.2.3 running on a soekris net5501. I've been having issues trying to get snort to work. I know the hardware is fine, I ran snort under OpenBSD, running it on the LAN and WAN interfaces at once with all rules active. It worked great, never complained much. The only pain was filtering false positives =P.
Under pfsense when I try to run it, it slowly eats up all my memory, then all my swap, finally causing snort to exit out. Is there some fundamental setting I'm missing? I'm running it more or less default on the WAN interface only, with about half the rules checked. It takes a while to exhaust memory and swap, but eventually does it. I have 512 megs of ram on the system, and 2 gigs of swap space.