Tag Archives: CentOS

Granting access to X server with xhost

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Every X server internally manages an ACL (Access Control List) of those hosts, that are allowed to connect. The server only authorizes connections from X clients, whose host is on that list and rejects access to all others. The xhost program is used to add or revert access to the X server for specified hosts. It’s also possible to specify… Read more »

Dealing with .rpmnew and .rpmsave files

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When an upgrade includes changes to a default configuration file, the package will write either a .rpmnew or a .rpmsave file instead of overwriting the configuration file on your system. Which file a package creates is up to the discretion of the package maintainer. From “Dealing with .rpmnew and .rpmsave files” By Bruce Byfield: An .rpmnew file contains the new… Read more »

Cleaning up locally-installed RPMs with package-cleanup

Sometimes, packages you never actually use get installed as dependency by yum (or even during initial installation by anaconda). package-cleanup is a great tool that helps you find packages not required by other packages. It it part of the yum-utils package which can easily be pulled with yum: 1. Find and review “unused” packages You can find packages not required… Read more »

Netboot CentOS using Attansic L1 Gigabit Ethernet

To update the initrd.img to load additional drivers early in the boot process, normally you would simply run /sbin/mkinitrd and let the script do the work. But what if the initrd.img used during the installation of CentOS lacks an important driver? Maybe you want to netboot CentOS, but the initial ramdisk CentOS provides doesn’t have the right modules for you… Read more »

sSMTP revaliases, aliases and mail.rc

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I already wrote about sending mails with ssmtp, a simple alternative to sendmail. But since I got a few questions (and I tend to forget myself) how to use ssmtp’s revaliases-file, here is a short reminder: /etc/revaliases, allows you to map a local user to a specific ‘From:’ address on outbound mail and to route that mail through a specific… Read more »

Installing phpMyAdmin on CentOS [Update]

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Because CentOS doesn’t pull all dependencies correctly, here is my little memory hook for installing phpmyadmin (and mysql, of course) After installing the packages, edit /etc/httpd/conf.d/phpmyadmin.conf and add the IP of your admin workstation to the line that begins with Allow from. For using phpmyadmin with cookie auth, you have to set a blowfish secret in /usr/share/phpmyadmin/config.inc.php: Update: Added php-mbstring

Adjusting your fanspeed with trinity (lm_sensors, pwmconfig and fancontrol)

Modern CPU throttling technology like Intel’s SpeedStep or AMD’s Cool’n’Quiet are quite fancy. They not only reduce the CPU frequency and the core voltage, the mainboard also detects an idling, cool CPU and therefore reduces the fanspeed. But what if the fanspeed is still to high while the CPU is doing nothing? Or maybe the fan doesn’t spin fast enough… Read more »

Mounting xen images

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Mounting images that contain only one partition is rather easy. But how to mount image with multiple partitions? kpartx is the solution! You can list all partitions within the image with kpartx can be used to create maps from the block devices And those maps can be mounted as usual