Dealing with portscans

[David Allen]

Over the last few weeks I've been getting numerous ports scans, each from
unique hosts.  The situation is more of an annoyance than anything else,
but I would prefer not seeing or having to deal with an extra 20-30K
entries in my logs as was the case recently.

I use pf for firewalling, and while it does offer different methods
(max-src-conn, max-src-conn-rate, etc.) for dealing with abusive hosts, it
doesn't seem to offer much in the way of dealing with repeated blocked
(non-stateful) connection attempts from a given host.

Short of running something like snort, is there a suitable tool for
dealing with this?  If not, I'll probably resort to running a cronjob to
parse the logfile and add the offending hosts manually.