Need some help configuring Login Whitelist

I want to configure the Login Whitelist function properly, because I keep getting a lot of failed login attempt emails and I’d really like that to stop.

Before locking myself out, I am wondering whether I have to use IPv4 or IPv6 IP addresses in the Login Whitelist. Or both?

I’m hoping the (static – I think?) IPv4 is enough, because I’m pretty sure my (dynamic) IPv6 address is constantly changing a little bit. Or does an IPv4 address changes as well?

If that’s the case, I have no idea how to use the Login Whitelist function properly. So if someone could explain how to use this function in the right way, I’d be very grateful!

Cheers.