Category: Linux
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Delete files older than
It is just one of those things that as an admin, you sometimes come across. There’s a directory somewhere that fills up with clutter. Every day, programs dump temporary files there or users upload stuff and before long, there are thousands of files of debris and cruft. How do you keep this directory neat and…
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Hardening Postfix
While there are plenty of good (and not so good) anti-spam solutions available, most of them cost a bit of money in terms of purchasing and licensing fees. Even without a dedicated appliance, there are several ways you can harden the Postfix MTA against spam and other internet nasties. In this article, we’re going to…
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Require TLS for certain domains in Postfix
Recently, I was asked if it was possible to require Transport Layer Security (TLS) for sending email for certain domains, through a specific relay. For added complexity, the list of domains would need to be updated daily. Of course it’s possible, I said. And yes, Postfix is up to the challenge. Here’s how to require…
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Using blacklists with iptables
If you have any kind of system connected to the Internet, you are no doubt aware that no matter how small or unimportant it might seem, it is frequently probed, tested or subject to various attempts at abuse. These attacks come from so many malicious hosts that it is impossible to keep track by hand.…
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Installing the VMWare View client on openSUSE 13.1
If, like me, you like to use the openSUSE Linux distribution, both personally and professionally and you need to connect to a VMWare View environment, you’ll be unpleasantly surprised: there’s no supported client for openSUSE or other RPM based distributions. There is however, an Ubuntu package..
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SSH tunneling error
When trying to set up a SSH tunnel through a remote host in order to bypass a pesky firewall, I received an error which I did not immediately understand.