Looking for a online port scanner

Basically, I have employees that work from home that use routers. We do not support routers. So I'm looking for a free online website that can basically do a scan to see what ports are blocked. They use programs like outlook(port 80) and an ATT vpn client(port 443).

Any ideas?

Here you go: https://www.grc.com/x/ne.dll?bh0bkyd2

that is a great reference :)