DenyHosts: Remove / Delete an IP address

Step # 1: Stop DenyHosts
# /etc/init.d/denyhosts stop

Step # 2: Remove Your IP From /etc/hosts.deny
# vi /etc/hosts.deny

Delete your IP address. Save and close the file.

Step # 3: Remove Your IP From /usr/share/denyhosts/data Directory
Cd to /usr/share/denyhosts/data
# cd /usr/share/denyhosts/data

You need to edit the following files using vi and remove the lines containing the IP address. Save the file.

hosts
hosts-restricted
hosts-root
hosts-valid
users-hosts
If you’ve static IP address add to allowed-hosts file. Any IP address that appears in this file will not be blocked by default (consider this as a whilelist):
# echo ‘1.2.3.4’ >> allowed-hosts

Step # 4: Start DenyHosts
# /etc/init.d/denyhosts start

Allow an IP:
nano /etc/hosts.allow
add the line:
sshd: Your_IP

check the logs:
tail -f /var/log/secure

And if you want to remove a banned IP address from the denyhosts:
# /etc/init.d/denyhosts stop
And then use the following lines to remove or delete the banned IP address completely:

# nano /etc/hosts.deny
# nano /var/lib/denyhosts/hosts
# nano /var/lib/denyhosts/hosts-restricted
# nano /var/lib/denyhosts/hosts-root
# nano /var/lib/denyhosts/hosts-valid
# nano /var/lib/denyhosts/users-hosts

Start deny host:
# /etc/init.d/denyhosts start
use grep for searching an IP:
#cd /var/lib/denyhosts
grep wanted_IP *

thanks to:
http://www.cyberciti.biz/faq/linux-unix-delete-remove-ip-address-that-denyhosts-blocked/
http://www.unixmen.com/install-configure-denyhost-centos/