Blocking many accesses to ssh port from single IP

[Steve Williams]

Hi,

I am running OpenBSD 3.7-stable, pretty standard install, spamd 
greylisting, httpd, sendmail.  Going over my log files, I have noticed 
that I am more and more coming under attach with dictionary based login 
attempts to the SSH port. 

I tried to search the mail list, but I can't seem to find any magic 
combination of words that would reveal the secret to me.  Reading 
pf.conf(5) didn't shed any light either..

Tonight I got 800+ attempts from the same IP.  I played with manually 
blocking the IP, but it was over before I got the firewall rules written 
and looked over them twice.

Is there any way to block/limit the number of connections to a port in a 
given time period?  I was getting around 5 connects per second from the 
same IP/PORT (in Hungary :-( ).

I can't think how this would work... unless there was a generic program 
like spamd in greylisting mode...  But I'm not the first person to have 
this problem, so there's likely a solution!  Can anyone shed some light?

Cheers,
Steve Williams