How To Calculate a TCP-IP Subnet Mask

If you’re a network administrator, chances are at some point you may need to set up a number of different networks on your IP range. In order to do this, you will need to know how to create different subnets.

There are two main things to remember when trying to calculate subnets. The first is that that default subnet for a range is 255.255.255.0. This subnet, that we all recognize gives you one network with 255 different addresses from 1 to 255. Fairly easy stuff so far. The second thing to remember is the formula needed to calculate a new subnet. For this we have to go back to basics and remember that the number 255 is made up in binary of 8 bits. To get the number 255, all those 8 bits would be set to 1, each one representing a number in decimal in the following sequence. (1, 2, 4, 8, 16, 32, 64, 128). If you add all these numbers together you get 255.

Set up a Linux media server

Do you have multiple machines around your house that would like to share a centralized server for multi-media? Having such a server for music allows for consolidation, ease of use, and space saving on client PCs. Of course to many users, the idea of setting up a multi-media server sounds like it would be a nightmare…especially on the Linux platform. That couldn’t be further from the truth.

The Firefly Media Server (formerly mt-daap) is a fast DAAP server that is simple to install and even easier to configure. Firefly resides on a single Linux machine that doesn’t have to be a powerhouse. In fact, you can install this lightweight server on Ubuntu Server and you’re almost ready to go. In this article you will see how to do just that – install and configure Firefly Media Server on Ubuntu Server.

Features

The Firefly server has all of the features you will want in a DAAP server:

Apache troubleshooting tips

How many times have you installed a LAMP server only to find Apache doesn’t seem to want to run right? Or you install a new module only to see Apache try to download pages as file, instead of displaying them on screen?

There are a hundred and one thousand things that can go wrong with any web server installation. From a fresh installation to an installation that has been running for a long time, you never know when something is going to cause your web server to go astray. When it does happen, it’s always nice to know that, usually, Occam’s Razor applies.

In this tutorial you will find some advice that will help you through some of the more common issues that can pop up with an Apache web server.

Is your server actually running?

Connect to a Windows Terminal Server from Linux

There are a number of reasons to have to connect to a Windows Terminal Server machine. Either you telecommute, you administer remotely, you work on the go, or you use Linux and have to use a Windows app for company business. No matter the reason, you have to be able to connect. From the Windows operating system there is a built-in application for making this connection. But what aboutLinux? How do you make this connection from within the open source operating system? Simple.

There are a number of good Linux terminal server clients available. In this article I will demonstrate how you connect to your server with the help of two of them: tsclient and krdc.

tsclient

What most people like about tsclient is that is very closely resembles the Microsoft tool that handles the same task. So there is already a level of familiarity to the application. But before you can use it, you have to install it. This is simple, just follow these steps:

Migrate users from one Linux machine to another

Have you ever had a need to migrate current running Linux users from installation to another? That would be a simple task if the user count was low. But  what happens when the user count is in the hundreds? What do you do then? If you’re not using LDAP, you know you will have to migrate the users’ data, passwords, etc from the old machine to the new. Believe it or not, this is just a matter of a few commands – not necessarily simple commands, but it’s not as complex as you would think.

In this article I am going to show you how to make this migration so your Linux users do not loose their data and their passwords are all retained.

What we migrating

The list is fairly simple:

• /etc/passwd - Contains information about the user.
• /etc/shadow - Contains the encrypted passwords.
• /etc/group - Contains group information.
• /etc/gshadow - Contains group encrypted passwords.
• /var/spool/mail - Contains users email (the location will depend upon the mail server you use).
• /home/ - Contains users data.

Unfortunately these files can not simply be copied from one machine to another – that would be too easy.  Just make sure you enter the following commands correctly.

Set up a Linux VPN Server with Gadmin-VPN-Server

here are so many reasons why a VPN Server makes perfect sense. For one, anyone with the credentials and the address can then gain access to the internal network from an external source. This enables users to work remotely and still have access to resources they wouldn’t otherwise have access to. There are obviously plenty of ways to set up a VPN server, but one of the most user-friendly means of setting up a VPN server on Linux is with the help of the Gadmin-VPN-Server tool.

The Gadmin tools are a set of GUI administration tools that allow for easy administration of various services, systems, and applications that would otherwise be challenging for the average user. One of those tools that is exceptionally helpful to have is the VPN Server tool. Let’s install it and set up an VPN

Running MDT 2010 Update 1 with Linux

If you ask Microsoft, it’s absolutely impossible to run MDT (Microsoft Deployment Toolkit) without an Windows Server. However, all you really need is a PXE-boot solution that provides support for booting ISO-files. Here’s a guide how you could do it running Debian on the server. Just remember the clients you deploy with MDT will still be Windows only. This is quite useful if you want to place a small Linux NAS close to the clients at a satellite office to save bandwidth without hosting a full scale server.

This guide assumes that you already have a Linux server running. This guide has been written using Debian GNU/Linux 6.0 ‘Squeeze’. We also assume your network has a DHCP server you have control over.

If you need help to setup Debian, please refer to other available guides on the internet.

Install and Configure Samba

We will use Samba as a file server for the MDT distribution share.

To install it run the command: