Category: IT
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Stand Up for Strong Security
Certain factions within the US Congress and the FBI are insisting on the government requiring US technology companies to grant the government special access to devices and cryptographic measures. In essence, they are asking for US technology to be insecure by design. Adding a backdoor for US government agencies is possible but there are serious…
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Smartphone Battery Myths, Explained
When I named this blog “Random musings, rambling opinions”, I was serious. So I bring you all kinds of interesting (hopefully) posts, ranging from how to secure your computer, to things about atheism, dinosaurs and now smartphone battery myths. Hope this helps someone! Over just a few years, the batteries in our smartphones have changed…
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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.…