Unassigned LAN IP leads to server suspension because of spoofing
Can you educate me on something I was not aware of?
I added a LAN IP address to my WireGuard server like this:
ip addr add 10.10.10.123/32 dev wg0
I happened not to use this IP for anything. The IP was pingable when connected to WireGuard, the server would respond.
The hosting provider suspended my server because of IP spoofing, that someone had been using that unassigned IP to spoof my public IP.
This was fixed easily, but now I have questions.
How is that possible? Given that there was no breach, it means that the unassigned LAN IP could be somehow used to act as the external IP?