The IMTA has the ability to reverse envelope from: and header addresses. Generally, this is used to turn the address form username@host.domain to the more public form first_name.last_name@domain so that recipients outside of the domain only see the latter form.
This functionality is not always activated. For instance, it is not active if the routability scope is set to Local System Users Only. To enable, set the option USE REVERSE DATABASE to 5 in /etc/opt/SUNWmail/imta/option.dat and make sure the list of channel keywords for the delivery channel does not contain noreverse.
Another cause of reverse address failure is the absence or incorrect configuration of the preferredrfc822originator LDAP attribute.
To further diagnose the problem, set MM_DEBUG to 5 in option.dat and activate the slave diagnostic output for the queuing channel. Restart the IMTA and reproduce the problem. Examine the debug output file created in
/var/opt/SUNWmail/imta/log. For information on how to use diagnostic output, see "To Configure Diagnostics Output" on page 128.