Category Archives: Sysadmin

Multiple IP uplinks with Gentoo

When your computer or server has access to multiple LAN segments with different address spaces and different gateways to the Internet, there’s a nice feature called policy routing that allows you to use all of them simultaneously without having to re-configure your network topology. This is especially useful when you want to increase the bandwidth and […]

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Top 25 vulnerability RSS feeds

One way to receive up-to-date reports about vulnerability issues is subscribing to vulnerability RSS feeds: they update on demand, they don’t rely on your mail subsystem and they don’t fill up your mailbox. The only drawback is that you could miss alerts if you don’t sync your feeds for a long time, but if you’re […]

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LUKS mermaids of remote unlock

Recently, I’ve browsed several how-to’s regarding the possibility of unlocking a LUKS root volume remotely using an SSH connection. For reference, the first of its kind is the one for Debian, published at Some of these how-to’s were posted to forums and mailing-lists and received many thankful comments from sysadmins wondering how to make […]

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Using screen as your login shell

GNU screen is a nice utility that allows running multiple interactive shells from the same terminal session and allows you to detach from your terminal while keeping those shells alive. Later on, you can re-attach to your background screen to get back to your shells. It has a lot more features like automatic session logging and […]

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The Microsoft hotfix tale

A few people on Earth still have a Windows 2000 machine laying around in their lab, mostly schools with severe budget cuts. Some time ago, one of these retro labs had a problem with roaming profiles: apparently Windows 2000 desktop machines refused to sync their profile on logoff. A collegue of mine asked my help […]

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Linux RAID disk wipeout

A common problem with Linux software RAID (aka md) happens when you try to use a disk that was previously part of some other disk array. Symptoms include: wrong volume size, unable to add device to raid, volume UUID mismatch. To fix the problem you need to use mdadm utility on the disk to cleanup: # […]

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Yo momma uses Ubuntu

Recently I replaced my mother’s PC, and I thought I could switch her to Linux. She was previously using Windows XP with several Open Source applications (Open Office, Firefox, Thunderbird, etc), so I decided to install Ubuntu 9.10, since it seems that it’s most devoted to non-expert users (she’s over-sixty and not inclined to change […]

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What evil lurks in OCFS2

In the beginning, Linux was a free general purpose OS and it was not clear how Linux companies would generate profits out of it. In 1999 RedHat company went public and started to develop a real business plan. After a few years, in 2003, one of its main competitors, SuSE Linux, was acquired by Novell. […]

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Gentooize Part 1: colorize console

One of the best lessons you can learn from Gentoo is you can export most of its juice to other OSes. I’ve been using Gentoo as main Linux distro since 2001. Currently I have a few setups where drawbacks of migrating to Gentoo would exceed benefits, so I decided to increase affinity by adding some […]

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Windows back-to-the-future bug

According to this advisory written by Tavis Ormandy, Windows has been exposed to a vulnerability for over 15 years! Microsoft will only release a patch for supported products, so if you have any Windows 2000 or earlier in your lab, the only way to fix is disabling DOS and WOWEXEC.

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