I am trying to unblock an IP from which I was doing some tests. I have followed the tutorials on the net:
$ sudo /etc/init.d/denyhosts stop
$ sudo vim /etc/deny.
If instructions above didn't help maybe denyhosts added IP to iptables firewall.
iptables -L -n -v | grep xxx.xxx.xxx.xxx
If you see something like that:
0 0 DROP all -- * * xxx.xxx.xxx.xxx 0.0.0.0/0
Remove required IP from firewall:
iptables -D INPUT -s xxx.xxx.xxx.xxx -j DROP
And restart networking to apply changes:
/etc/init.d/networking restart