Archive for the 'Linux' Category



Oct 06 2016

Processing CSV Files with Perl and Bash

Published by under Linux

Olivier, a friend of mine, had to parse a CSV file and took the opportunity to benchmark the performance of 3 programming languages.   The file contains server names and disks he needs to add up into a hash table in order to get the total disk space for each server. He assumes on his […]

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Sep 13 2015

Apache Proxy Permission Denied 503

Published by under Apache,Linux

You are proxying Apache requests to another server and your browser throw a 503 error back: “Service temporarily unavailable” Looking at the http logs in /var/log/httpd/ssl_error_log, I am getting (13)Permission denied: proxy: HTTP: attempt to connect to (*) failed You may also get: AH01114: HTTP: failed to make connection to backend SELinux is most […]

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Aug 27 2014

LVS: a Free Load-Balancer for Microsoft Exchange

Published by under Linux

Microsoft Exchange traffic can be load-balanced with Microsoft NLB but it requires to set up 4 Exchange servers for the sake that NLB isn’t compatible with (Exchange) cluster. Most Microsoft guys do not recommend it.Among NLB downsides, Exchange services are monitored with a basic ping, meaning the service is considered to be active even if […]

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May 01 2013

Change Linux Keyboard

Published by under Linux

One can change the current session keyboard mapping with loadkeys. To load the French keyboard map, simply run loadkeys fr   Available keymaps can be found in /lib/kbd/keymaps/ You can even create your own

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Nov 30 2012

IPTables Traffic Redirection on Linux

Published by under Linux

Whether you need to redirect telnet or ssh connections through a server because you don’t have direct access to your final destination or you’re planning a web server migration, traffic forwarding comes in handy in many situations.This is easily achieved on Linux distributions that come with IPtables. Yes, iptables isn’t just for ACL rules, but […]

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