rate limit for incomming connections

for example for port 22 (ssh) and 3 times a minute

iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent \
 --set

iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent \
 --update --seconds 60 --hitcount 4 -j DROP