VampSo a few weeks ago some of our Centos 5.4 and OEL 5.5 servers started exibiting strange connectivity problems. Monitoring started alerting that hosts were down when they weren't; some boxes could ping target hosts and some couldn't; some boxes became unresponsive when interfaces were failed over, and the strangest of all is that some of the boxes would magically "repair" themselves. Like I said, strange.
rhel
Poor Man’s eSATA Drive Hot Swap without AHCI or Hotplug Support Under Linux
Unfortunately, hot-swapping an eSATA drive is a bit more complicated than hot swapping a USB drive. First off, your BIOS needs to support AHCI (click here for more info on AHCI), and your SATA controller also needs to support it as well. Secondly your OS, needs to specifically support hot plug, and in the case of Windows 7, it wont boot if you change to AHCI after the OS has been installed.
RHEL6 – Simple Iptables How To
Your mother and I were talking last night about how important it is to properly configure Iptables, and how despite that fact, many just choose to disable it. So today we are going to discuss iptables.
RHEL6 — Troubleshooting SELinux Violations
Dear Reader: Welcome to my third and not final instalment on SELinux. The first two can be read here and here. They are exciting reads and are sure to have you on the edge of your seat. Anyway, the best way to implement SELinux sucessfully is to know how to troubleshoot when things aren't going your way. If you panic at the first sign of trouble, you are just going to end up turning off SELinux and not reap the rich rewards that it will bring you in life. Now that I have convinced you to run SELinux lets get started.
RHEL6 – SELinux Modes and Contexts
SELinux, or Security-Enhanced Linux as its known by the guy who invented it, is a Linux feature that provides an additional level of security by setting rules for which processes can access which files, directories, ports, etc. Display and Modify SELinux Modes: You can use /etc/sysconfig/selinux to change the default SELinux mode at boot, and … Continue reading RHEL6 – SELinux Modes and Contexts
RHEL6 – Managing Swap Space
Swap space on a Linux box is an area on disk that is used to hold inactive memory pages. This occurs when the system needs more memory then is currently available, so it swaps these inactive memory pages to disk.
RHEL – Managing Passwords with Chage
To understand the chage command if might be best to make sure that you understand the /etc/shadow file, so lets look at a line from mine. Note that ":" is the field separator.