How-To: Fight SPAM with Postfix RBL

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 […]

How-To: using Python Virtual Environments

A nice thing about Python is that there is tons of modules available out there. Not all those modules are readily available for your distro and even if there were, chances are that a newer release with new features is already out there. You might not always want to install those modules system wide, either […]

How-To: Automatically logout idle bash session

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 [...]

How-To: WiFi roaming with wpa-supplicant

wpa_supplicant can be used as a roaming daemon so you can get your system to automatically connect to different network as you are going from one location to another. This come in pretty handy on headless machines where you rely on network connection to be up in order to be able to access the machine. [...]

How-To: Make a file Immutable/Write protected

There might be time when you want to make sure that a file will be protected from accidental/automated change/deletion. While one can protect a file/directory in some ways by removing write permissions using standard file permission on Unix already can save you from some situations, there is more that can be done on Linux. The [...]

Debian 7.0 Wheezy released

Debian 7.0, code name Wheezy, is finally released. This new release of comes with some interesting new features such as multiarch support and tools to deploy private cloud based on OpenStack and Xen Cloud Platform (XCP). For the first time, Debian supports booting using UEFI. Debian 7.0 Wheezy will be running on Linux 3.2. the [...]

How-To: tail multiple files with multitail

Many times you will end up tailing multiple files simultaneously. There is a sweet linux utility called multitail that will let you tail multiple files at the same time within the same shell. And not only will you be able to tail multiple files! You will also be able to run multiple commands and tail [...]

How-To: Reboot on OOM

Ever had your linux box getting Out of Memory (OOM)? Cleaning up after the OOM killer kicked in to find out that even though OOM killer did a decent job at trying to kill the bad processes, your system ends up in an unknown state and you might be better of rebooting the host to [...]

How-To: find which program consumes your bandwidth with nethogs

Let’s continue the network monitoring serie with yet another use case…. the “What program is using my bandwidth?” problem while not imposible to solve, still remains a pain. What if there were some kind of top for network? NetHogs is a nifty tool that will do that for you and will help you finding what [...]

How-To: monitor network bandwidth usage with vnstat

There is many tools out there that help in monitoring network usage, collect statistics and generate graphs so we can view what happened at a given date/time. Anyhow, finding the bandwidth usage over an hour/day/week/month can be really tricky. vnstat is a suite of daemon and client programs that monitor network bandwidth usage. A pro [...]

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