This seems like it would be such an easy thing to do - but not for me.:-(
So I created a node and called it "Solarwinds" used polling address 74.115.12.20 and set it to External Node: No status.
I then created a SAM Template called "External Website Check) and added to monitors HTTP & Weblink, I then added my "Solarwinds" node to test against.
I get "Unable to connect to the remote server", We have no idea why it doesn't work.