Dot-decimal settings exist to store parameters such as IP and MAC address. Like strings, they consist of a number of bytes. The difference is that when a dot-decimal setting is read, ddstr() is executed on its members. For example, if the internal value of the setting consists of bytes 192, 168, 1, and 40, then "192.168.1.40" is returned when the setting is read. When the setting is written to, the ddval() is executed, so "192.168.1.40" because a set of 4 bytes (192, 168, 1, and 40) again.