@futurebird There are a couple of ways a static IP could be assigned in an Intranet.
Usually you get a dynamic IP address from DHCP, a service running on the router you connect to. It identifies a network interface (your network card or wifi) by its MAC address, then assigns an IP address for a certain period of time.
The most reliable way to assign a static IP address is for it to be reserved on the DHCP server, so that MAC always gets the same IP.