• How to add and remove user accounts in Linux

    Creating user accounts on Linux can be easy. If you run Linux as a Desktop there are likely a few GUI tools to add and modify User Accounts. Unfortunately, since most Linux Servers run without GUIs, you must know the commands and how to use them to create and remove users.

    This guide will present two options for user account creation and two options for removing user accounts.

  • How to autostart TeamViewer in Linux

    There are plenty of remote control software solutions for Linux and plenty of them allow for administration of the console session. In Windows we would refer to this as "Session 0" or the native desktop interface that a user would normally need to be physically present at a keyboard and monitor connected to that computer or server in order to see. TeamViewer is another "remote control software". Conveniently the TeamViewer development team has made TeamViewer available for Windows, Mac, and Linux.

    This tutorial will assist in configuring your machine to auto-start TeamViewer before a session has been initiated so that the user is able to initiate the login of any user allowed to login to the system.

  • How to disable and re-enable user accounts in Linux

    Creating user accounts on Linux can be easy and was discussed in another tutorial. Many people need to create and remove user accounts but few people actually consider wanting to disable them.

    Luckily if you wish to disable a user account, it isn't that hard. This guide will demonstrate how to easily disable or enable an account using a very common command.

  • How to enable IP Forwarding in Linux

    Most Linux desktops and servers have no reason for enabling IP Forwarding. Typically we would only want to enable this setting on servers that act as VPN server, Proxies, or load balancers. There are a few reasons for enabling this setting on desktops. For instance you may be required to enable this setting to do penetration testing.

    Regardless of your reasons, this guide will help to identify the files that need to be edited and commands that need to be run in order to enable IPv4 Forwarding. Although IPv6 existing, IPv4 is still the most common version to be enabled and this guide will therefore focus on IPv4 Forwarding.

  • How to mount CD/DVD in Linux

    Most GUI-based Linux distributions provide automatic mounting of tools for CD/DVDs. Automatic mounting tools take the need to learn and know CLI (command line interface) commands away from many beginning Linux users. This helps by reducing the learning curve for most new users.

    Linux Servers usually run without a GUI (Graphical User Interface). From time to time, it is necessary to install software from a CD/DVD. Since this function is not always automatic, here is a guide to mounting CD/DVDs on Linux.

  • How to mount ISO files in Linux

    Most GUI-based Linux distributions provide several viable packages to access archives such as .zip, .tar, and even .iso files

    Linux Servers usually run without a GUI (Graphical User Interface) and therefore many of the GUI tools are unavailable. From time to time, it is necessary to install software from a .iso file. Since this function is not automatic, here is a guide to mounting .iso files on Linux.

  • How to set ownership and permissions using chown and chmod in Linux

    Occasionally you may need to change the ownership or permissions of a file or provide access to files for a specific user or a group of users. Ownership of a file is important in determining how permissions are given. Every file and folder is owned by a user and a group. The primary owner of a file does not neccessarily need to be in the group which "owns" the file or folder.

    This guide is to help change ownership and permissions in Linux using some of the most commonly used options.

  • How to set Static IP Address on Debian-based Linux

    Most servers have static IP addresses. You can either set a reservation in your DHCP scope (this could spell disaster if the DHCP server is unavailable or there is a networking related issue) or you can manually set a static IP address in Linux configuration files.

    This guide will help in manually setting a static IP address through editing of Linux configuration files.

  • How to setup Tor as a Transparent Proxy on Ubuntu Linux

    Tor is a great product to help protect your anonymity online. The Tor Project website can be used to gather more information about its use and how it works. Tor does not create complete anonymity but helps by encrypting and then bouncing your traffic around to other Tor relays before it exits an exit-node onto the Internet unencrypted. A benefit of encryption is that it is not normally analyzed by network filters and therefor bypasses.

    Proxies are frequently used to mask the real location of a user, log traffic coming in and out of a network, circumvent network filtering, or in some cases to gain access to network resources that are local to the proxy but separated by a firewall or not directly available from a remote location. Traditionally proxy configurations must be set in every software package you with to use the proxy server (in most circumstances this is a web browser usually by means of specified port and/or username and password). Transparent Proxies are proxies that do not need to be configured by an end-user in order to function.

    In many cases it is the interest of users to do more than tunnel just web browsing traffic. This guide will assist in configuring Tor as a transparent proxy and configure firewall rules to forward all network traffic regardless of TCP/UDP port through the Tor proxy. By doing this all network traffic leaving your local network will exit encrypted and then sent through the Tor Network.

  • How to setup VLANs on Debian-based Linux

    Occasionally it is necessary to segment networks into VLANs (Virtual LAN). VLANs are a layer 2 technology which allow for segregation of broadcast domains. VLANs help to logically separate different types of traffic. Segmenting network traffic into data, VoIP, and/or Video Streams can help to provide better manageability and security. VLANs are typically applied at a network switch port by specifying the exact VLAN data and Voice traffic can use, but can also be specified at a Linux virtual port adapter and the network switch can enable 802.1q trunking.

    This guide will help in setting up VLANs through editing of Linux configuration files.

  • How to SSH login without passwords

    SSH is the typical manner most Linux/UNIX administrators use to remotely access and run commands against a Linux/UNIX server or desktop. Occasionally typing a username and password becomes tedious. Having to type your username and password can put a halt to automating processes.

    This guide will help in automating SSH login without a password from a Linux/UNIX system to another Linux/UNIX system.

  • How to use redirects and pipes in Linux

    A large part of the power and flexibility of Linux/UNIX-like Operating Systems comes from the design of it's commands and programs. Programs are usually designed to operate efficiently by performing a single function. Programs can be generated by combining multiple basic commands. One command operates to produce data that is used to run the next set of commands.

    This guide explains the basic difference between the different types of data streams with which a command line operator may come into contact.

    Data Streams

    There are three main types of streams used or produced by programs in UNIX-Like Operating Systems. There are nonstandard input and nonstandard output, but we will not be discussing those types of data streams.

  • How to use X11 Forwarding using SSH

    X11 Forwarding through SSH enables a user to run a software application from a remote system using the CPU and memory of the remote system while rendering the GUI of the application locally. This can be very handy if your chosen desktop is Linux, Windows, or Mac (this tutorial will not cover Mac) but either the application is not cross platform or unavailable due to licensing, your local system does not have the local resources to run the chosen application, or you need access to network resources which are local to the target of the SSH connection but not local to the machine you are currently using (i.e. a server behind a firewall/gateway device that has port forwarding for SSH to the remote host to which you are connecting).

    There are plenty of remote control software packages which would allow for full desktop rendering. Sometimes it's not necessary to display a full desktop. In a Microsoft Windows environment this would be most closely similar to the technology of RemoteApp.

    X11 Forwarding is easy to setup and use. Best of all, X11 Forwarding through SSH is encrypted which means the entire SSH communication is encapsulated in a the SSH Session. This tutorial will assist in configuring the remote server to allow X11 Forwarding through SSH and will provide local commands or software needed to establish connection to the X11 Session through SSH.