imsimta test -rewrite provides a test facility for examining the MTA's address rewriting and channel mapping process without actually sending a message. Various qualifiers can be used to control whether imsimta test -rewrite uses the configuration text files or the compiled configuration (if present), the amount of output produced, and so on.
If a test address is specified on the command line, imsimta test -rewrite applies the MTA address rewriting to that address, reports the results, and exits. If no test address is specified, imsimta test -rewrite enters a loop, prompting for an address, rewriting it, and prompting again for another address. imsimta test -rewrite exits when CTRL-D is entered.
When testing an email address corresponding to a restricted distribution list, imsimta test -rewrite uses as the posting address the return address of the local postmaster, which is usually postmaster@localhost unless specified by the MTA option RETURN_ADDRESS in the MTA Option file.