Installing Nagios on existing VMWare Server

My question is when Installing Nagios on existing VMWare Server, how to configure httpd port? (this is a test installation)

VMWare Server is installed on RHEL, and the admin console is configured to use Apache port 80.

Nagios should work on this server by configuring it to use port 8080 or port 81.

httpd starts with a failure the error states that port 80 already is being used.

adding Listen *:81 to httpd conf files does not help.

This should work as far as I know.

I dont see how to configure Nagios to use another port, is this an Apache configuration or a Nagios config, could I get some help?

I did not see a way to establish which port to use during installation, did I miss something?

I know I can reconfigure VMWare to use port 81, but want to learn about Nagios, I would expect to be able to configure Nagios to use another port besides default.

Your problem has nothing to do with your Nagios configuration. Adding a new port to listen on with your Apache ports configuration will not be enough. You will need to configure a new virtual host to use with your Nagios installation in your sites configuration, since you mentioned that your default virtual host is being used by your admin console.

httpd.apache.org/docs/2.0/vhosts/examples.html

should be here