DenyHosts

DenyHosts is a utility developed by Phil Schwartz which aims to thwart sshd (ssh server) brute force attacks.

Please refer to https://github.com/denyhosts/denyhosts for more information.

Installation

Source Distribution

If you downloaded the source distribution file (DenyHosts-#.#-tar.gz) then:

$ tar zxvf DenyHosts-2.8.tar.gz       (Where #.#.# is the version)

$ cd DenyHosts-2.8

as root:

# python setup.py install

This will install the DenyHosts modules into python's site-packages directory.

Binary Distribution (rpm, deb, etc)

It is assumed that you are familiar with installing a binary package on your particular operating system. If you are unsure how to do this, you may wish to install from source instead.

All Distributions

DenyHosts requires that a configuration file be created before it can function. The sample configuration file denyhosts.conf contains most of the possible settings and should be copied and then edited as such:

# cp denyhosts.conf /etc

# <edit> /etc/denyhosts.conf

(where is your preferred text editor such as emacs, vi, etc)

The sample configuration file contains informational comments that should help you quickly configure DenyHosts. After you have edited your configuration file, save it.

Next, if you intend to run DenyHosts in daemon mode (recommended) copy the sample daemon-control.dist script as such:

# cp daemon-control-dist daemon-control

Edit the daemon-control file. You should only need to edit this section near the top:

###############################################
#### Edit these to suit your configuration ####
###############################################

DENYHOSTS_BIN   = "/usr/bin/denyhosts.py"
DENYHOSTS_LOCK  = "/var/lock/subsys/denyhosts"
DENYHOSTS_CFG   = "/etc/denyhosts.conf"

These defaults should be reasonable for many systems. You should customize these settings to match your particular system.

Once you have edited the configuration and daemon control files make sure that the daemon control script it executable (by root).

# chown root daemon-control

# chmod 700 daemon-control

Starting DenyHosts Manually

Assuming you have configured DenyHosts to run as a daemon, you can use the daemon-control script to control it:

# daemon-control start

You should refer to the daemon log (typically /var/log/denyhosts) to ensure that DenyHosts is running successfully. If you notice any problems you may wish to consult the FAQ at http://www.denyhosts.net/faq.html

If you wish to run DenyHosts from cron rather than as a daemon, please refer to the FAQ.

Starting DenyHosts Automatically

Method 1 (preferred)

Create a symbolic link from /etc/init.d such as:

# cd /etc/init.d
# ln -s /usr/share/denyhosts/daemon-control denyhosts

If you have chkconfig installed you can then use it to ensure that DenyHosts runs at boot time:

# chkconfig --add denyhosts

If you do not have chkconfig (or similar) installed you can either manually create the symlinks in /etc/rc2.d, /etc/rc3.d, /etc/rc5.d but that is beyond the scope of this document.

Method 2

Add an entry into the /etc/rc.local file:

/usr/share/denyhosts/daemon-control start