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Webmail interface is one of must-have services for any mail server. Most of us are used to native email client software, but what if your favorite client software is not available for any reason? For example, you have left your laptop at home, or your phone's data plan just went dry, or maybe you are just travelling. An alternative way to access a mail service in such cases would be to use the webmail interface of your mail server. As long as there is web browser with Internet connectivity, you should be able to use the webmail interface.

If you want to find out where a given IP address is physically located on earth, there are quite a few online GeoIP lookup services you can try (e.g. geoiptool.com). These online services are mostly powered by freely available GeoIP databases such as those from MaxMind. Besides using such web-based services, there are different ways to query the GeoIP databases, notably via the Linux command line. In this tutorial, I am going to describe how to geolocate an IP address from the command line in Linux.

In the world of mail servers, MailScanner is one of the best open source software for virus scanning and spam detection. MailScanner relies on pre-installed anti-virus and anti-spam software to check incoming and outgoing emails for malicious content or patterns of spamming. This makes sure that the mail server does not participate in the distribution of malware and unsolicited spam emails. It also helps preventing the mail server IP from becoming blacklisted, keeping the mail server records clean. This tutorial will focus on setting up MailScanner along with Clam Antivirus and SpamAssassin in a CentOS system. The procedure should work on RHEL as well.

Raspberry Pi celebrated its second birthday last week. Since its debut on February 29, 2012, Raspberry Pi has ushered in a whole new generation of tiny, inexpensive, single-board computers. Numerous Raspberry Pi based DIY project ideas are popping up over the web, and there are many use cases of Raspberry Pi as low-cost learning media in the developing world. Celebrating its second birthday, I am going to share in this post several interesting facts about Raspberry Pi.

A video editor allows you to handle post-production video editing which typically involves arranging, cutting, pasting, trimming, and otherwise enhancing (e.g., adding various effects to) video clips through the timeline interface. In modern video editing software, things like multi-codec import/transcoding, non-linear video editing, or even HD video support are pretty much standard nowadays. In this post, I am going to show 10 popular video editing software available on Linux.

Antivirus and anti-spam protection are the among the most important security features for a mail server. Unix/Linux based mail servers are typically invulnerable to malware and viruses, and there is a very slim chance that the server itself may get infected. On the other hand, the operating system of an end user device may not always be so secured. We certainly do not want our mail server to accept or distribute malware embedded emails. So setting up antivirus software on a mail server is a must. In this tutorial, we will be looking at how to secure our mail server by setting up Clam Antivirus, SpamAssassin and MailScanner.

There are different ways to manage virtual machines (VMs) running on KVM hypervisor. For example, virt-manager is a popular GUI-based front-end for VM management. However, if you would like to use KVM on a headless server, GUI-based solutions will not be ideal. That is when virsh comes in handy. virsh is a command-line tool for managing guest VMs. Underneath it, virsh relies on libvirtd service which can control several different hypervisors including KVM, Xen, QEMU, LXC and OpenVZ. In this tutorial, I will demonstrate how to run KVM from the command line by using virsh on Debian or Ubuntu.

Network Manager is a feature-rich network configuration service which is used by default in most Linux desktop environments nowadays. While Network Manager comes with various sophisticated features, you might just prefer the old plain network service. This tutorial describes how to disable Network Manager in various Linux desktop environments.

Webmail is undoubtedly an essential part of any mail server. While native email client software has typically more features compared to webmail services, accessing IMAP or SMTP server ports via an email client from outside of the trusted network can sometimes be tricky. Moreover, while you need a designated workstation, laptop, or mobile device to use an email client, you can use webmail services from anywhere as long as you have an Internet connection. This tutorial will focus on setting up RainLoop webmail on an Ubuntu server running Apache.

While a MAC address is a manufacturer-assigned hardware address, it can actually be modified by a user. This practice is often called "MAC address spoofing." In this tutorial, I am going to show how to spoof the MAC address of a network interface on Linux.

One of the easiest way to screen capture a particular web page as a PNG image is by using CutyCapt, which is a convenient command line Linux tool for converting any HTML webpage to a variety of vector and bitmat image formats (e.g., SVG, PDF, PS, PNG, JPEG, TIFF, GIF). Internally, CutyCapt uses WebKit rendering engine to export webpage rendering output to an image file. Built with Qt, CutyCapt is actually a cross-platform application available for other platforms such as Windows as well.

As a versatile network monitoring tool, Nagios can monitor the health of various network elements such as routers and switches. Among others, Nagios can be configured to monitor BGP sessions of a router, and generate alerts whenever there is something wrong in existing BGP session(s). Several BGP monitoring plugin tools exist for Nagios. These tools are useful in monitoring critical BGP peers of a router, and generating alerts for them. This tutorial will explain how to monitor BGP neighbors using Nagios plugin tools.

Wanted to watch TV on your Linux box, and preferably for free? FreetuxTV is an online TV player which was originally developed to let the subscribers of French ISPs (e.g., Free, Orange, SFR) to watch live TV channels streamed by those ISPs. Over time, FreetuxTV has added additional free online TV, web radio and webcam channels to the list, and now the (crowdsourced) FreetuxTV database carries channels in over 50 different languages.

Mail server admins may often have to deal with different types of requirements based on service policies or customer-specific requests. This tutorial will cover common cases of mail server administration. More specifically, it will show how different mail server requirements can be met by tuning parameters of Postfix and Dovecot.

One of the most popular and useful projects with Raspberry Pi board is turning RPi into a media center box. This article will discuss how to set up a media center on Raspberry Pi using two of the most popular media center images: Raspbmc and OpenELEC. Both images use XBMC as built-in media player software.

Livestreamer is a command line interface (CLI) client which, upon given a streaming URL, retrieves live streaming video from the URL, and pipes it into a native video player running on local host. So with Livestreamer, you can enjoy live streaming from various sources via a much stable and lightweight video player such as VLC or mplayer, without opening a web browser.

It is no secret that faster loading web sites lead to higher visitor engagement, retention and conversion rates. Every 100 msec of latency costs Amazon 1% drop in its sales, while 500 msec extra delay means 20% less traffic and revenue for Google. If there is a way to speed up your web server without upgrading to a more powerful server, there is no reason not to try it. This tutorial describes how to optimize Nginx web server to speed up its performance with Google's PageSpeed module.

Every mail server administrator dreads his or her server becoming compromised by spammers. A lot of effort, time and even money is spent on securing mail servers and making sure that the servers do not become open relay. This tutorial will focus on setting up a Postfix SMTP server to use Dovecot SASL for user authentication. Simple Authentication and Security Layer (SASL) is a framework that can be used by many connection-oriented Internet protocols for securing data, servers and users. With SASL enabled, Postfix will not accept any incoming SMTP connections without proper authentication.

Often referred to as the "swiss army of knife" for TCP/IP networking, Netcat is an extremely versatile Linux utility that allows you to do anything under the sun using TCP/UDP sockets. It is one of the most favorite tools for system admins when they need to do networking related troubleshooting and experimentation. This tutorial presents a few useful netcat examples, although the sky is the limit when it comes to possible netcat use cases.

This tutorial describes how to compile and install Nginx web server from source. While Nginx is available as a standard package on major Linux distros, you need to build it from source if you want to enable a custom third-party module. Note that Nginx does not support loadable modules like Apache web server. You need to choose and include third-party module(s) to use at compile-time.