For the most part, yes - with a few exceptions.
As a provider of a hosted eCommerce solution, Shift4Shop outsources its web servers from a U.S. Based hosting server provider that adheres to applicable export compliance regulations.
As such, there are certain IP addresses that are blocked because they originate from countries that are subject to U.S. trade and economic sanctions.
Currently, these countries are:
Cuba
Iran
North Korea
Sudan
Syria
Therefore, your store will not be accessible to visitors originating from these countries.