Is there anything out there that I can install on my PFSense (a large Intel PC with 5 NICs) that will diagram my network and display it on the PFSense web pages?
Some sort of add-on would be ideal, but another web-based solution would not be bad either.
I don't mind feeding it the IP's to monitor.
I want to avoid nagios (I want to spend 10 minutes not 10 days setting it up)
Don't think so, no.
Active, automatic network diagram spending no time and no money? Good luck.