Tutorial

How To Install DenyHosts on Ubuntu 12.04

Published on June 15, 2012

How To Install DenyHosts on Ubuntu 12.04

Status: Deprecated

This article covers a version of Ubuntu that is no longer supported. If you are currently operate a server running Ubuntu 12.04, we highly recommend upgrading or migrating to a supported version of Ubuntu:

Reason: Ubuntu 12.04 reached end of life (EOL) on April 28, 2017 and no longer receives security patches or updates. This guide is no longer maintained.

See Instead:
This guide might still be useful as a reference, but may not work on other Ubuntu releases. If available, we strongly recommend using a guide written for the version of Ubuntu you are using. You can use the search functionality at the top of the page to find a more recent version.

About DenyHosts

DenyHosts is a security tool written in python that monitors server access logs to prevent brute force attacks on a virtual private server. The program works by banning IP addresses that exceed a certain number of failed login attempts.

Step One—Install Deny Hosts

DenyHosts is very easy to install on Ubuntu

 sudo apt-get install denyhosts

Once the program has finished downloading, denyhosts is installed and configured on your virtual private server.

Step Two—Whitelist IP Addresses

After you install DenyHosts, make sure to whitelist your own IP address. Skipping this step will put you at risk of locking yourself out of your own machine.

Open up the list of allowed hosts allowed on your VPS:

sudo nano /etc/hosts.allow

Under the description, add in any IP addresses that cannot afford to be banned from the server; you can write each one on a separate line, using this format:

sshd: 12.34.45.678

After making any changes, be sure to restart DenyHosts so that the new settings take effect on your virtual private server:

sudo /etc/init.d/denyhosts restart

Step Three—(Optional) Configure DenyHosts

DenyHosts is ready use as soon as the installation is over.

However if you want to customize the behavior of DenyHosts on your VPS, you can make the changes within the DenyHost configuration file:

sudo nano /etc/denyhosts.conf

By Etel Sverdlov

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Etel Sverdlov

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1458e7509aa5f47ecfb92536e7dd1d • December 21, 2012

Can you run denyhost and fail2ban together or will they step on each other?

Etel Sverdlov

DigitalOcean Employee

• December 21, 2012

You can use them together if you wish—they should not really interfere with each other.

klevisurf • January 3, 2013

Hello! Nice tutorial, but i have put on hosts.allow my ip to connect via ssh but the denyhost automaticlly put some ip on hosts.deny. Need some specific configuration? why do not recognise the hosts.allow ip? best regards

Moisey Uretsky

DigitalOcean Employee

• January 3, 2013

Hi, please paste your hosts.allow file there may be a typo or it may be misconfigured which is why you had that issue.

digitalocean84396 • January 23, 2013

you need to sudo before using nano to edit those files

Etel Sverdlov

DigitalOcean Employee

• January 23, 2013

Updated! Thank you!

digitalocean84396 • January 29, 2013

better yet, use sudoedit instead of sudo nano

jered • February 16, 2013

If I reboot my VPS, will the rules still be in place?

atendimentoticombr • February 18, 2013

I know that most users reading this tutorial has already followed other tutorials which explain the nano editor commands to save (ctrl+x, y, enter), but mentioning them here will be useful for novice.

lloydfaulk • February 23, 2013

What would you do if the ip you allow changes for was on a dynamic ip?