This overrides the
lockbox limit if set.
The lockbox limit must be enabled as well, or both limits are ignored.
If set, allows only the set number of IPs to access the lockbox account. These days people
have different IP addresses, but also share login details with friends. This useful security option can help
prevent multiple logins from the one account.
It's worth considering the fact that many people have laptops, tablets and phones these days and log in from work
and home locations. Also people without fixed IP addresses will have a different IP should they restart their router. You should factor this into your limit.
If you set a limit of 1, the login IP must always be the same as the signup IP. This is the strictest setting.
Set to 0 to disable. Note that there are no restrictions for the master login credentials.
IMPORTANT: For this feature to work, 'login' events MUST be enabled.