Deny Hosts
==========

*denyhosts* (http://denyhosts.sourceforge.net) is a python script that acts as
a dynamic blocker for SSH and other services. It monitors connection attempts
and adjusts */etc/hosts.deny* if too many failed connection attempts are made.

::

  sudo apt-get install denyhosts


Sometimes valid connection attempts fail, and a user may end up being denied
access to the host. In this case, the script *unban* below can be run by an
administrator to revert the block imposed by *denyhosts*::

  #/bin/sh
  REMOVE=$1

  /etc/init.d/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

  /etc/init.d/denyhosts start