Probing External Websites (Web Server Up/Down)

I'm looking for advice. We have some external websites managed by our vendors that seem to go down frequently. For accountability reasons we need to start independently monitoring them. 

Can we use Domino probes to fetch a URL from a non-Domino server and alert us when there is no response?

If we cannot use the built in monitoring tools I could write an agent. Has anyone done this?

Subject: web server monitoring

Not sure if you can do it with Domino 8 built-in probes, it was not possible in R7. I am using our own tool Larm-O-Matic for monitoring web and Notes:http://www.botstation.com/products/larm-o-matic/about.php