Categories
Red Hat Enterprise Linux / CentOS

Install Postfix (email server) in Linux

This article shows you how to install and configure a simple mail server called Postfix. It can be used to send emails or act as a email relay server for internal network wherein only one Server is allowed access to Internet and then all clients hosts will redirect email to this Postfix email relay server.

We would need to install two packages via YUM.

Categories
Red Hat Enterprise Linux / CentOS

Secure /etc/fstab in Linux

Its best to secure /etc/fstab as it contains all the mount locations and can lead to boot issues if any novice person tinkers/plays around with it. The secure mode can only be enabled /disabled by root user only and completely secure. There is a simple one line command for that as given.

Categories
Red Hat Enterprise Linux / CentOS

Add and Mount LVM Volume in Linux

Its possible add a LVM volume on the fly. The steps would involve formatting the newly added disk with LVM and creating a mount point and adding the new volume to it. The whole process would involve creating Physical Volume followed by Volume group and then assigning logical volume and mounting it to a mount point.

Categories
Linux Red Hat Enterprise Linux / CentOS

Get rid of SSH error message “WARNING REMOTE HOST IDENTIFICATION HAS CHANGED”

In Linux when you try to SSH it may at times give you this warning that REMOTE HOST IDENTIFICATION HAS CHANGED. It usually happens when the hostname or IP has changed of a host or the host was rebooted and generated a new fingerprint Key ID. No need to worry, it can be removed by a single command and you would be up and running in no time.

Categories
Red Hat Enterprise Linux / CentOS

Setup Nagios Core on CentOS/Red Hat

Setup and Configuration guide for Nagios Core on any Fedora/Linux based OS (incl. CentOS & Red Hat). This guide would allow you to setup Nagios Monitoring Server up and running in roughly 15 mins. The process would involve installing yum packages and then compiling Nagios from source.

NOTE: You need to a be a ROOT user to compile and install Nagios Core.