Category Archives: Linux

Nagios and SNMP traps

Posted on August 29, 2013 by blogger

It has been explained many times over the internet, so I won’t cover that. One thing you have to pay attention to is, if you run snmptt as a daemon, be sure that it has the right to write to … Continue reading →

Posted in Computer, Linux, Networking, Virtualization | 1 Comment

Ubuntu netbooting needs a “new” kernel parameter

Posted on July 23, 2013 by blogger

After a few hours spent trying to find why Ubuntu 12.04 would not download a preseed file while netbooting, I stumbled upon this bug bugs.launchpad.net/ubuntu/+source/casper/+bug/923219 . I needed to add “IPAPPEND 2” after the APPEND directive in the pxelinux config … Continue reading →

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Exim, DNS blacklists and fail2ban

Posted on February 12, 2013 by blogger

Last week, I saw an huge “spam” outbreak on my MX servers. Instead of ~200k rejected SMTP connections, I had ~3M connections and it was rising. This caused some minor issues with the frequent log parsing as the log file … Continue reading →

Posted in Computer, Linux | 2 Comments

Varnish and Apache log files

Posted on February 12, 2013 by blogger

If you use Varnish with an Apache server and analyze Apache log files (with AWstats or something else), you probably saw all requests were coming from 127.0.0.1 (or the IP address Varnish is on). You’ve probably forgotten to change the … Continue reading →

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Debian/Linux MX server

Posted on October 6, 2012 by blogger

I needed to install some incoming mail servers (MX servers) to filter emails before delivering them to customers servers. So the need is to accept mails for a fixed list of domains, check for viruses and spams, then route them … Continue reading →

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Ubuntu 12.04 on HP Microserver N40L

Posted on July 4, 2012 by blogger

Just some thoughts and things I’ve done. The hardware is the following: the Microserver itself, 2x 4GB DDR3, one 16GB USB flash drive, some 2TB SATA hard drives, Logitech S-150 USB speakers, and a GT520 HDMI+DVI graphic card. Installation on … Continue reading →

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Wowza 3 + Ubuntu 12.04 setup

Posted on May 16, 2012 by blogger

2012-08-13 Update: simple monitoring with Cacti. The goal I want to have a clean Wowza setup for a live streaming platform. The access to the streaming server will be open but every other service (management interface, ssh, web server, etc) … Continue reading →

Posted in Computer, Linux, Uncategorized | 6 Comments

Linux: OpenVZ, partie 1

Posted on June 14, 2011 by blogger

OpenVZ est une solution de virtualisation au niveau du système d’exploitation. Ce n’est pas vraiment de la virtualisation mais plutôt du cloisonnement de processus, un peu comme un chroot, en mieux. Il n’y a qu’un kernel et il exécute successivement … Continue reading →

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Linux Debian: installation automatisée

Posted on June 13, 2011 by blogger

Après avoir installé des dizaines de Debian manuellement, et comme il semble que je vais devoir déployer des dizaines de Debian semblables dans un futur proche, il était grand temps de découvrir l’automatisation du Debian Installer. La documentation du preseeding, … Continue reading →

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Linux Kernel: impact de KSM

Posted on June 11, 2011 by blogger

Suite au post précédent, j’ai activé KSM sur une machine hébergeant deux petites VM. Avant l’activation, la mémoire ressemblait à ça: _____________total_______used_______free_____shared____buffers_____cached Mem:______16471120____3936616___12534504__________0_____469648_____239828 -/+_buffers/cache:____3227140___13243980 Soit environ 3840MB utilisés. Après quelques dizaines de secondes et un premier full_scan, on voyait déjà … Continue reading →

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