We will see various types of commands for shutdown and reboot for Linux in this article.
Shutdown Syntax:
shutdown [OPTION]… TIME [MESSAGE]
Ethtool Utility
1. List Ethernet Device Properties
When you execute ethtool command with a device name, it displays the information about the ethernet device.
How to schedule Recurring Cron jobs on Linux
Unix provides a service called cron that runs programs repeatedly on a fixed schedule. Most experienced administrators consider cron to be vital to the system because it can perform automatic system maintenance.
How to correct the MAC address after Clone RHEL or CentOS in VMWare
Cloning machines in VMWare is really straightforward thing. However once you do clone a machine, you’ll be left with new MAC addresses for the network cards. In a typical scenario the cloned RHEL or CentOS machine will boot up without the local network interface. You’ll typically see the following during boot.
How to Fix eth0 network interface when cloning RedHat, CentOS
If you clone a VMWare or VM, you’ll notice that it kills your network interfaces throwing errors like the one listed below:
#ifup eth0
Device eth0 does not seem to be present, delaying initialisation
Configure Bonding Device on Red Hat Enterprise Linux 6
Introduction
Bonding (or channel bonding) is a technology enabled by the Linux kernel and Red Hat Enterprise Linux, that allows administrators to combine two or more network interfaces to form a single, logical “bonded” interface
Telnet not obeying the per_source limit
Issue
We are trying to limit the telnet connection from any individual IP address to 10 in RHEL. However this is not working and it seems that each source can have unlimited connections. Our configuration is set to limit the connections, via the per_source value in /etc/xinetd.conf to 10 as shown below:
How to patch OpenSSL’s Heartbleed Vulnerability
How to patch OpenSSL’s Heartbleed Vulnerability
First you need to understand that not all version of OpenSSL are vulnerable.
Below are the version of OpenSSL that are affected by this bug.
Understanding Linux file Permissions
What is “crashkernel=X@Y” in /etc/grub.conf
“crashkernel=X@Y” is a kernel parameter for Kdump.
Kdump requires some memory reservation for the second kernel(capture kernel).
When kdump is enabled, (physical memory – X) will be allocated.
