So everyone else has good points but there’s one other part I don’t think was mentioned.

Most ISPs use a PON based network. This lets them connect one fiber in their network and “split” that to up to 128 (or more, depends on the OEM) customers. You need a either GPON (Gigabit passive optical network) or XGS-PON (10 gigabit symmetrical passive optical network) SFP module and usually the ISP has to get a serial number off of that module to provision the proper data service.

This is contingent upon the ISP being willing to do that. The one I currently work for, we really don’t do that except for businesses.

Most ISPs (especially smaller ones it seems) just run a basic DHCP server with leases expiring at a set interval. As long as your stuff is on and working when the lease renews, you’ll pull the same IP forever.

It’s not a war crime if it’s the first time……