VPN and incoming connections difficulty

[Kandala]

Without a VPN, incoming connections have to be routed through your home router to your node by configuring port forwarding on your router
With a VPN, the port forwarding configuration has to be done at the VPN gateway

Some VPN providers refuse to support port forwarding (eg IPVanish)
Some don't mention port forwarding in any of their Web pages or documentation (eg IPredator)

The most popular VPN provider, Private Internet Access, only supports port forwarding on some of their gateways, and they publish a list of the gateways and the port forwarding works fine - but then a Bitcoin node can only listen on port 8333, and that port might be used by someone else on the gateway you want to use

AirVPN supports port forwarding on all their gateways, but again, you have to check whether 8333 is available for you, or whether they supply an arbitrary list of 20 ports you're allowed to