Setup DKIM with Postfix on Ubuntu Server

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…

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Fixing Nagios “error: Could not stat() command file”

One common configuration issue with Nagios 3 running on Ubuntu is getting the Service Commands menu to work correctly in the web portal. By default, it is visible in the UI, but disabled on the server backend. In Ubuntu, you will recieve the cryptic error Could not stat() command file pointing to /var/lib/nagios3/rw/nagios.cmd. This can…

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