Debian/Ubuntu Tips and Tricks

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Debian/Ubuntu Tips and Tricks

How-To: Prevent SPAM with Apache’s mod security

Posted by chantra on 6th November 2014

WordPress is a great piece of software to run a blog, it is flexible, has tons of plugins are developed for it and updates are really easy to do. To fight spam comments, there is already the Akismet plugin that does a really good job.
While Akismet catches the spam comments and put them in a separate location, making it easy to delete them, as the number of spam grows, WordPress can take long to empty the purge the flush comments and the best option becomes to use a manual SQL query to flush them.
In this article, we will see how we can use RBL to prevent spammer from posting to WordPress's comment page and at the same time, lift a bit of load from the server.
While the rules work for WordPress, with a bit of modifications, it will be easy to get this setup working for any kind of blog/website.

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Posted in Administration, HowTo, HTTP, Networking, System | 1 Comment »

How-To: Fight SPAM with Postfix RBL

Posted by chantra on 26th September 2013

Spam, spam everywhere! If you are hosting your own mail server, fighting spam can become tricky. Antispam solutions do catch a fair amount of them, but still many spam email can still make their way through.

RBL (Real-time Blackhole) is a database of known spammy IPs which is accessible over DNS. Depending on the response received from the DNS server, the IP is classified as spammy or not.

This tutorial will show you how to set up RBL with postfix.

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Posted in Administration, HowTo, Networking, System | 1 Comment »

How-To: Automatically logout idle bash session

Posted by chantra on 15th July 2013

It can be useful to have a bash session automatically closing after some time. One of the obvious reason you might want this to happen is to make sure that no console is left with root access unwillingly.

Bash comes ready for this and can be configured to automatically terminate after waiting for activity for a given time.

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Posted in Administration, General, HowTo, System | No Comments »

How-To: OpenVPN on Debian Squeeze with Username/Password authentication

Posted by chantra on 16th January 2013

OpenVPN is a SSL based VPN software that runs on most OS. It is simple to install and run.

In this tutorial, I will go over the steps needed to configure OpenVPN on Debian Squeeze to provide a full VPN tunnel, this is particularly useful when you want to access internet from non-trusted networks such as free hotspots...

There are many ways of setting up OpenVPN, a common one is to use a unique certificate for each users. Another one is to have each user authenticate with a username/password.

In this article, we will be setting OpenVPN to authenticate users using PAM.

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Posted in Administration, HowTo, Networking, Softwares, System | No Comments »

How-To: Set up a L2TP over IPSec VPN using a Radius backend — page 3

Posted by chantra on 18th June 2010

This entry is part 3 of 3 in the series How-To: Set up a L2TP over IPSec VPN using a Radius backend

Using freeradius for authentication

Here I am going to consider that the freeradius server is set up correctly, meaning that you can already authenticate your users with freeradius using radtest utility.

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Posted in Administration, HowTo, Networking, System | No Comments »

How-To: Set up a L2TP over IPSec VPN using a Radius backend — page 2

Posted by chantra on 18th June 2010

This entry is part 1 of 3 in the series How-To: Set up a L2TP over IPSec VPN using a Radius backend

XL2TP

Now, let's get on the next phase: XL2TP.

Packages Requirements

You can install xl2tp with the following command:

# apt-get install xl2tp

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Posted in Administration, HowTo, Networking, System | 1 Comment »

How-To: Set up a L2TP over IPSec VPN using a Radius backend

Posted by chantra on 18th June 2010

This entry is part 1 of 3 in the series How-To: Set up a L2TP over IPSec VPN using a Radius backend

Even though I pretty like OpenVPN, there is still some devices that might not support the TUN/TAP driver needed by OpenVPN.

Take IPhones, Android phones for instance, you need to root them in order to get that feature, assuming somebody has already cooked a ROM for your device.

L2TP is quite and old standard that allow setting up VPNs.

On the other end, it does not provide any kind of encryption mechanism, and as such, it is pretty common to get L2TP running over an IPSec link.

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How-To: Apache2 authentication using MySQL backend — page 2

Posted by chantra on 17th December 2008

This entry is part 1 of 2 in the series How-To: Apache2 authentication using MySQL backend

3. Creating users

Here we will be using sha1 password. To create a password, you can use the following command:

# echo -n 'password' | sha1sum
5baa61e4c9b93f3f0682250b6cf8331b7ee68fd8 -

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Posted in Administration, HowTo, HTTP, Networking, System | 5 Comments »

How-To: Apache2 authentication using MySQL backend

Posted by chantra on 17th December 2008

This entry is part 1 of 2 in the series How-To: Apache2 authentication using MySQL backend

this tutorial will explain how to use a MySQL backend in order to authentication users against your Apache website.

To achieve this we will use Apache2 and its auth_mysql module.

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Posted in Administration, HowTo, HTTP, Networking, System | 1 Comment »

How-To: encrypted partitions over LVM with LUKS — page 3 — install and config

Posted by chantra on 12th July 2008

This entry is part 3 of 3 in the series How-To: encrypted partitions over LVM with LUKS

4. Installing the system

we are now going to install the distro over our layout. Start the installer and make sure you choose manual partitioning. Then set up your filesystem like the one on the screenshot.

luks encryption over-lvm ubuntu installer

luks encryption over-lvm ubuntu installer

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Posted in Administration, HowTo, System | 3 Comments »