Nagios Support Forum

Hello
I'd like to create infrastructure for monitoring a website from various ISPs.
I think about using Virtual Private Servers with CentOS at a few locations. They'll check webpage availability, maybe login/logout tasks etc.
Simple diagram:
a website--------<-------VPS(public IP)---------<----------|firewall with 443 open|----<---Nagios Core (private IP)

The acquired statistics data should be stored and then pulled from the VPSes by Nagios Core server at main site. The connection between Nagios and VPS should be encrypted and initiated by Nagios on destination port 443 (the only firewall rule).
I also need to do some VPS server maintenance then I think about using shellinabox (for maintenance) if VPS will have no administration panel.

What software components should I use to achieve the described goal and how to configure them?
Thanks.

We can definitely help with the Nagios side of things, but for recommendations on VPS management I would suggest asking on a forum dedicated to such a thing.

The biggest bottleneck here is going to be port 443. That's great for SSL, not so great for running checks. Passive checks won't work due to the private IP. I suppose you could do some web scraping similar to how you are checking the websites themselves, in order to get the information back to the Nagios Core in the private IP address space.