Feature request: Show a warning if peer is not publicly dialable

I use ipfs-desktop 0.8.0.0 (and go-ipfs 0.4.21) on Windows 10.

IPFS ports are open on my Windows Firewall and my router by default. If I run IPFS normally I can connect to 250+ peers and my shared files can be accessed without too much extra delay.

I use a VPN service frequently. This service doesn't support port forwarding, so if I'm on VPN my ports appear to be closed. In this case I can connect to fewer peers (~40) and the access to my files are significantly slower.

I think it would be beneficial to have a small indication somewhere (maybe on the peers page) if the ports on the computer seem to be closed.
A brief explanation of the drawbacks of this would be motivating, and we could even offer some helpful links to configure the firewall and/or the router.