Use to specify the domain origin which is appended to the host name with a period in between. This forms the fully qualified domain name for a host; for example, if MVSADM1 is the host name and YOUR.ISP.COM is the domain origin, then MVSADM1.YOUR.ISP.COM is the fully qualified domain name.
Rules:
The origin name usually has imbedded dots, that is, periods.
The maximum length allowed for domain origin is 66.
The domain origin consists of one or more labels separated by periods.
Each label must be at least one character long.
The first character of a label must be an alphanumeric.
Each subsequent character of a label string must be an alphanumeric or a hyphen.
The last character of the domain origin must not be a period.