# Functions
IPAddress validates if the given string is a valid IP address.
NameField validates the name field.
OptionalNameField validates the name field when optional.
RestrictedPorts validates if the given port is restricted.
# Variables
ErrFieldEmpty is returned when a field is empty.
ErrInvalidIPAddress is returned when the given string is not a valid IP address.
ErrRestrictedPort is returned when the given port is restricted.