I have been using these protocols without deep understand how everything works under the hood.
I understand a process of tunneling as follows
- When we are using protocols like OpenVPN, IPSec, SSH they operate on the same level of OSI stack or above where the IP protocol is located (3-d level)
- When using the mentioned above protocols all traffic (like TCP, IP) is encrypted inside data part of the underlaying protocol like IP.
- When traffic reaches a VPN server it is decrypted and redirected according the embodied data.
I can't understand the following case.
In order to even connect to a VPN server we are using at least the IP protocol to reach the server. Because all traffic on the Internet is being routed by IP addresses. Therefore in that case how can we operate on a level that is lower than the IP protocol. How do we reach a VPN server? We cannot reach a server by MAC address only as far as I know.
Could you explain this ?
Thank you so much !