The ${client_flags} macro holds the flags specified by the ClientPortOptions option's Modify parameter (See this section). This ${client_flags} macro is given a value only after a connection is made because the Modify flags can vary by the family of the connection. If no Modify flags were specified, ${client_flags} is given an empty string as its value. The value letters from the ClientPortOptions=Modify option are stored into this macro after the connection is made. Each letter is separated from the others by a space, and capital letters are doubled . That is, for example, if that option was declared like this: ClientPortOptions=Modify=bcE the value of the ${client_flags} macro would become: b c EE Capital letters are doubled so that they can be detected in rules. Recall that rules view their workspace in a case-insensitive manner (that is, e is the same as E ). Doubling allows the LHS of rules to be designed like this: R $* e $* match a lowercase e R $* ee $* match an uppercase E ${client_flags} is not used in the default configuration file, but is available for you to use in rules of your own design. Note that a $& prefix is necessary when you reference this macro in rules (that is, use $&{client_flags} , not ${client_flags} ). ${client_flags} is transient. If it is defined in the configuration file or in the command line, that definition can be ignored by sendmail . |