19 Jan 2010 Change ethernet settings using ethtool
Force network speed on a network card to 100 MBit Full Duplex and in the same time disable auto negotiation
# ethtool -s eth0 speed 100 duplex full autoneg off
These settings are active until you reboot the machine or restart the network.
In order to keep this change on each system reboot, append the following line in the following Redhat file /etc/sysconfig/network-scripts/ifcfg-eth0
ETHTOOL_OPTS="speed 100 duplex full autoneg off"
An alternative tool to use to change the settings is mii-tool.
Posted by Hans-Henry Jakobsen
25 May 2009 Replace RPMforge packages with Redhats own on a RHEL5 system
This post came to life after experiencing some upgrade problems with missing dependencies and RPM packages from RPMforge and Redhat Enterprise Linux Client release 5. The prosess to remove or replace the packages was to remove RPMforge as a package repository and replace the blocking packages with Redhats own packages.
The process of replacing RPMforge packages with Redhats own packages
First we remove rpmforge as package repository
rpm -e rpmforge
This command removes the /etc/yum.repos.d/rpmforge.repo file.
Then we list all packages installed from the RPMforge repository to get an overview of the packages causing problems on the system.
rpm -qa --queryformat %{NAME}-%{VERSION}-%{ARCH}-%{RELEASE}\\n|sort|grep el5.rf
The result
dnsmasq-2.47-x86_64-1.el5.rf libsndfile-1.0.17-x86_64-1.el5.rf lftp-3.7.12-x86_64-1.el5.rf ...
The rf ending tells you that these packages are RPMforge packages. This command also tells you if it is 32bit (i386) or 64bit (x86_64) packages. I’ve described the prosess of removing 32- and 64bits packages in a earlier post named Remove duplicate packages when querying the rpm database.
Howto remove 64bit packages
yum remove libsndfile.x86_64
Next we will download the packages we want to replace, in my case dnsmasq
On a RHEL5 system
yumdownloader dnsmasq
If you don’t have yumdownloader in your system you have to install the yum-utils package.
On a RHEL4 system
up2date -d dnsmasq
Then we replace the RPMforge RPM package with Redhats own package
# rpm -Uvh --replacepkgs --oldpackage dnsmasq-2.45-1.el5_2.1.x86_64.rpm Preparing... ########################################### [100%] 1:dnsmasq ########################################### [100%]
If you don’t use the –oldpackage option you might get an error message like this
package dnsmasq-2.47-1.el5.rf.x86_64 (which is newer than dnsmasq-2.45-1.el5_2.1.x86_64) is already installed
I continued removing RPMForge packages until yum managed to resolve any unresolved dependencies.
Tags: RedHat, RHEL4, rhel5, rpmforge
Posted by Hans-Henry Jakobsen
23 Dec 2008 Force a user to change password upon first login
This is how you can force a Redhat user to change his password upon first login on a Redhat 5 installation. This might work on other versions and distributions…
- First lock the account to prevent the user from logging in until the change has been made
- Change the password expiration date to 0 to ensure the user changes the password during the next login attempt
- To unlock the account after the change do the following:
# usermod -L <username>
# chage -d 0 <username>
# usermod -U <username>
Posted by Hans-Henry Jakobsen
18 Sep 2008 Redhat documentation in one place
http://www.redhat.com/docs/manuals/enterprise/ is a documentation page I always return to when I manage Redhat Enterprise Linux systems.
Redhat has put a lot of effort in their documentation and even allow you to download them as PDF documents.
The documentation below is for RHEL5.2
| Deployment Guide | May 21, 2008 | |
| Installation Guide | May 21, 2008 | |
| Virtualization Guide | May 21, 2008 | |
| Cluster Suite Overview | May 21, 2008 | |
| Cluster Administration | May 21, 2008 | |
| LVM Administrator’s Guide | May 21, 2008 | |
| Global File System | May 21, 2008 | |
| Using GNBD with GFS | May 21, 2008 | |
| Linux Virtual Server Administration | May 21, 2008 | |
| Using Device-Mapper Multipath | May 21, 2008 | |
| Tuning and Optimizing Red Hat Enterprise Linux for Oracle 9i and 10g Databases | Nov 2007 | |
| Online Storage Reconfiguration Guide (Beta) | July 2, 2008 |
These documents is a great resource if you plan to become a RHCT or RHCE.
Posted by Hans-Henry Jakobsen
17 Sep 2008 Disable IPv6 on Redhat RHEL4
First you remove this line from /etc/modprobe.conf if this line exists.
alias net-pf-10 ipv6
Add the following line to /etc/modprobe.conf
alias net-pf-10 off
Reboot the system. IPv6 is now disabled.
To re-enable IPv6, remove the alias net-pf-10 off line from /etc/modprobe.conf and reboot the machine.
I’ve also made a post about how to disable IPv6 on RHEL5.
Posted by Hans-Henry Jakobsen
