Thank you for the video, for the record, netplan uses systemd-netword in headeless system (you can for example check with systemctl status systemd-networkd)
If you minus(ed) the original IP address, would the new IP replace the old one? Or would you have to somehow change the original IP in dhcp? I apologize, I'm a bit new to this. Also, all cards on the table: I'm trying to change an IP address on another machine to a new IP address because there was a data leak. For security reasons, I need to make sure that the old IP and the new IP don't match.
Many networks assign IP addresses via DHCP, but servers, for example, are often configured with a static IP address. This situation is when you need more than one IP address. Sometimes you'll need an address on two separate networks.
Not usually. The system’s default route usually is enough, and for a secondary IP for internal LAN traffic, no routing is required, just a direct connection.
