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.
Here's what worked for me on CentOS 6.7
./daemon-control stop/etc/hosts.deny/usr/share/denyhosts/data/hosts/usr/share/denyhosts/data/hosts-restricted/usr/share/denyhosts/data/hosts-root/usr/share/denyhosts/data/hosts-valid/usr/share/denyhosts/data/users-hosts/usr/share/denyhosts/data/allowed-hosts. This file simply expects one IP per line. Any IP address that appears in this file will not be blocked../daemon-control start