If the FILTER option is specified, the LIST command will be followed by one or more lines representing one or more PREDEFINED filters to be applied at the server.
The filters are applied in the order in which they follow the
LIST command. Their format is just like that of
FILTER information returned from the LIST command (see
subsection 
), except that the execution-location field must always
be SERVER, and the first four tokens (``ATTRIBUTE LINK
FIELD FILTER'') are omitted. The format is:
FILTER filter-type SERVER pre-or-post
PREDEFINED filter-name
ARGS filter-arg
The server will know that there are no more filter-specifying lines either when the end of the message is reached or it encounters a line that does not begin with the token FILTER.