portscans

After a couple of years, I have started to use FreeBSD again. Previously I was using Linux, and in all my servers I have installed "PSAD" package, which detect the Port Scanners IP addresses and bans them through IPTabels rules. I have searched the same in FreeBSD but does not exit. something...

I don't fully understand ICMP. Some Internet servers, as I've read, can function perfectly with ICMP completely blocked, but I don't necessarily want to block them all in my firewall. Which ICMP types can be completely blocked (from any direction) to mitigate portscans? Would blocking all ICMP...