Can't tell If The OpenVPN Server I Setup Is Encrypted using Wireshark?

Question

This might sound dumb, but I set up an OpenVPN server on a Synology NAS. When I connect via the client at home to the server, everything works for.

I know you can read packets in Wireshark. If I start sniffing on My WiFi that I'm connected to at home, packets show for the OpenVPN protocol and there are few lines that say Synology (I believe this is a handshake) but everything else, every line of data is gibberish so I'm assuming it's encrypted?

That also said, when I connect to the VPN another local area connection appears in Wireshark as an adapter to sniff. If I sniff the new local network this is NOT encrypted, but isn't that normal?

Essentially you're sniffing the new adapter itself locally as soon as you connect via the client? Or is that NOT normal? Why does it show gibberish like it's encrypted on the WiFi via Wireshark, but not the new connection created upon connection to the VPN called Ethernet 2?

Answer 1

The VPN creates a virtual network interface and sets a route so all traffic goes through this interface. If you sniff on this VPN interface everything will be in clear. But everything which is put into this VPN interface gets encrypted and then send trough another more real network interface (WiFi in your case) to the VPN endpoint. That's why if you sniff on WiFi you see everything encrypted.

At the VPN endpoint you then have the same setup, i.e. the encrypted traffic comes in through the "physical" interface, gets decrypted and then comes out in plain on the VPN interface.