NagiosGraph is an addon for Nagios that take the performance data from Nagios services and create graphs that you can use to see your network health. Install NagiosGraph First we will install the package prerequisites: Next we will download NagiosGraph (download the lastest version) Next we will extract Nagios Graph…
NRPE is a client side application for executing Nagios plugins. The Nagios server communicate with remote system over TCP Port 5666 using this plugin. NRPE must be installed on all the remote systems needs to monitor by Nagios server. Nagios server sends instruction to the NRPE server using check_nrpe plugin. Install Nagios…
In this tutorial, we’ll walk you through each step of installing Nagios Core on Ubuntu 22.04. You will have a Nagios setup that is fully operational by the end of this article, which will make it easier for you to keep a close eye on your network and systems. Update…
DKIM is an email authentication method that uses a digital signature to let the receiver of an email know that the message was sent and authorized by the owner of a domain. To enable DKIM on your domain with Zimbra you will need to use the zmdkimkeyutil utility You can…
I recently experienced an issue when I was connected to the Zimbra admin portal, in that the Server Status stats were not updating. When I ran a zmcontrol status all of the services where showing as running. To resolve this I restarted the logging service: The stats run every two…
To change the date or time you can use the touch command as with the following example: The switches are as follows: -a = accessed date and time -m = modified date and time -t = timestamp – use YYYYMMDDhhmm[.ss] time format To verify they are all the same, use…
Finding the new Disk Once the new physical or virtual hard drive has been installed on the system and is visible to the operating system. Once added, the new drive should automatically be detected by the operating system. Typically, the disk drives in a system are assigned device names beginning…
This post will walk you through setting up DKIM with Postfix on your Ubuntu 18.04, 20.04 or 22.04 Server. Setting up DKIM First, install OpenDKIM which is an open-source implementation of the DKIM sender authentication system. Then add postfix user to opendkim group. Edit OpenDKIM main configuration file. Uncomment the following lines. Replace simple with relaxed/simple. Then…
I recently came across an issue on an Ubuntu 20.04 installation recently when I setup Postfix using a smart relay with authentication. But when mails were sent, the following error was being recorded: I did some research and found I needed to install the libsas12-modules. I though I would share…
Iptables is the software firewall that is included with most Linux distributions by default. This post guide provides a quick reference to iptables commands that will create firewall rules for everyday scenarios. Allow Loopback Connections The loopback interface, also referred to as lo, is what a computer uses to forward network connections to…