I use pfSense as a load balancer to direct traffic to two different machines. I've experienced strange behavior when I restart the virtual environment, the load balancer marks it as offline, but won't notice when it comes back online. On top of that, I can't ping the firewall from the VE or vice versa, yet all the other machines on the lan segment can talk to one another.
I think I finally figured out how to fix the situation, if I refresh the filters, the IP comes back online. I had tried resetting the states but that didn't work. It could have been a coincidence that the machine came back online when I refreshed the filters, so I'll have to try it again and confirm it next time I restart the VE.
While I was working on the firewall, I also set the Advanced -> Traffic Shaper and Firewall Optimization Option to "conservative". The firewall serves mostly email and web traffic, and I've specifically set the web traffic state to expire quickly, so I am trying to improve email performance by increasing the default state time. If it causes any issues, I'll switch it back. The notes for the conservative setting say:
tries to avoid dropping any legitimate connections at the expense of increased memory usage and CPU utilization.
but I have 512MB of memory in the machine, with a 600Mhz PIII Coppermine processor, so I should be OK. Besides, my state table usually has less than 1000 entries out of a maximum of 10000.