Archive for August, 2009

Switching between the KDE and GNOME window managers on Centos and Fedora Linux hosts

I recently switched a Fedora host from the GNOME window manager to KDE. This exercise allowed me to familiarize myself with how X and the various window managers are organized on Fedora hosts, and I thought I would jot down how to switch between window managers for future reference. When a Fedora host is booted […]

Using the ssh config file to set specify remote usernames

I periodically need to access remote systems using different userids (I didn’t have control over the account creation process, and unfortunately LDAP isn’t in use :( ). While I could use the username@host syntax to specify a userid, I find it easier to list the userids in the .ssh/config configuration file. Here is a sample […]

Restarting X and the GNOME window manager on Linux hosts

I useGNOME as my primary desktop at work, and periodically need to restart the Xserver / windowing environment to pick up new changes. If I have an X environment up and running, I will send a cntrl + alt + backspace to restart the X server. If for some reason I’m not able to send […]

Monitoring traffic across a Solaris 802.3ad link aggregation

I manage a number of Solaris hosts that push a fair amount of data each day. These servers utilize Solaris 802.3ad link aggregations, which contain anywhere from 4 to 8 physical NICs. Monitoring the bandwidth across the links in an aggregation is a snap with Solaris, since most of the dladm subcommands support the “-s” […]

Securing Linux file systems that don’t contain executables

Linux comes with a slew of mount options, several of which are useful for locking down what can and can’t happen inside a file system. Three options I find super useful are noexec, nosuid and nodev. The noexec option disables execution for files that reside within a file system, nosuid disables execution of setuid executables […]

Making sense of cron in Centos and Fedora Linux

CentOS and Fedora Linux use a set of directories in /etc to control when jobs run. These directories take the following form: /etc/cron.hourly – jobs that run once per hour /etc/cron.daily – jobs that run once per day /etc/cron.weekly – jobs that run one per week /etc/cron.monthly – jobs that run once per month To […]

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