I am not looking for a failproof way to ban all non-relevant ip's. I'm looking for a method to exclude 99% of traffic based on IP ( if possible) and that i kno

I am not looking for a failproof way to ban all non-relevant ip's. I'm looking for a method to exclude 99% of traffic based on IP ( if possible) and that i know how i can get in if the IP changes and it isn't updated automatically on the server ( as a failsafe).