I wish New Relic would support plain old ICMP ping. That would be nice. You used to be able to implement it using their Scripted API thing (which is just sandboxed Node), but at some point they broke raw socket support, which broke every ping NPM in existence. I think you can still make it work if you run a private minion, but that's more effort than I want to spend.
https://newrelic.com/platform/synthetics