Each entry is a logical line, with physical lines terminated by a backslash (\) to indicate continuation. Entries are made up of options delimited by blank space. Each option is a name-value pair in the following format:
Values can be colon-separated lists. No blank space is allowed within an option assignment.
Comment lines begin with a pound sign (#), and they occupy the entire line up to a newline character. Blank lines are ignored (even within multiple-line entries).
There types of Permissions file entries are:
When a remote machine calls you, its identity is questionable unless it has a unique login and verifiable password.
LOGNAME entries contain a LOGNAME option and MACHINE entries contain a MACHINE option. One entry can contain both options.