connections from dialup IP's

[dave]

Hello,
    Last evening i had a pretty determined dialup user try to ssh in to my
system as root, the logs showed he tried for over 15 minutes. What i'd like
to know is is there a way of dropping a connection from an IP if it connects
more than x times in a minute? Or any other suggestions of dealing with
this? I did a host lookup on the IP, 211.206.125.39
which came back not found which kind of tells me he got offline. Suggestions
welcome.
    Also i'm not familiar with the .kr domain i'd like to block connections
from that one as well, same reason this one 4 minutes 165.132.58.56
Thanks.
Dave.