====== Remove a host that denyhosts has banned ======
 
**Denyhosts** is a utility that automatically bans IPs who attempt to ssh in to your server and get three wrong passwords. 

This is great when people are dictionary-attacking your **SSH server**, but less good when you have actual users who might get their //password wrong//.  

<code>
#/bin/sh
REMOVE=$1

service denyhosts stop

cd /var/lib/denyhosts

for THISFILE in hosts hosts-restricted hosts-root hosts-valid users-hosts;
do
mv $THISFILE /tmp/;cat /tmp/$THISFILE | grep -v $REMOVE > $THISFILE;rm /tmp/$THISFILE;
done

mv /etc/hosts.deny /tmp/
cat /tmp/hosts.deny | grep -v $REMOVE > /etc/hosts.deny;
rm /tmp/hosts.deny

service denyhosts start
</code>

Needs to run as //root//.

OR 

<code>

#/bin/sh
REMOVE=$1

service denyhosts stop

cd /usr/share/denyhosts/data

for THISFILE in hosts hosts-restricted hosts-root hosts-valid users-hosts;
do
mv $THISFILE /tmp;cat /tmp/$THISFILE | grep -v $REMOVE > $THISFILE;rm /tmp/$THISFILE;
done

mv /etc/hosts.deny /tmp/
cat /tmp/hosts.deny | grep -v $REMOVE > /etc/hosts.deny;
rm /tmp/hosts.deny

service denyhosts  start
</code>

Source:   http://www.aquarionics.com/2009/05/13/to-remove-a-host-that-denyhosts-has-banned

{{tag>Denyhosts debian secu script}}