11.2 Name Syntax
Names are listed in a dot notation (for example, abc.head.company.com). They have the following general syntax:
string.string.string .........string.
where the first string is a computer name, followed by the name of the lowest inserted domain, then the name of a higher domain, and so on. For unambiguousness, a dot expressing the root domain is also listed at the end.
The entire name can have a maximum of 255 characters. An individual string can have a maximum of 63 characters. The string can consist of letters, numbers, and hyphens. A hyphen cannot be at the beginning or at the end of a string. There are also extensions specifying a richer repertoire of characters that can be used to create names. However, we usually avoid these additional characters because they are not supported by all applications.
Both lower and upper case letters can be used, but this is not so simple. From the point of view of saving and processing in the DNS database, lower and upper case letters...
