An option file may be used to control various characteristics of the local channel. This local channel option file must be stored in the IMTA configuration directory and named l_option (for example, /etc/opt/SUNWmail/imta/l_option).
Option files consist of several lines. Each line contains the setting for one option. An option setting has the form:
value may be either a string or an integer, depending on the option's requirements. If the option accepts an integer value a base may be specified using notation of the form b%v, where b is the base expressed in base 10 and v is the actual value expressed in base b.