Subaddresses and address reversal

New in 7.0.5, the MTA&#x27;s address reversal logic has been extensively  redesigned to improve the handling of subaddresses. Previously the presence of a subaddress would prevent address reversal from occurring. (This long-standing behavior was a remnant of the past when if a user was sophisticated enough to put on a subaddress, one could presume that  the user was sophisticated enough to have already specified the exact  address that they wanted to send from---so altering such an address  wouldn&#x27;t be necessary and indeed would be dubious. However, nowadays  many other behaviors and  side-effects  are triggered via address  reversal so matching regardless of subaddress is typically desirable,  and further the old assumption that reversal is no longer desired in  such cases is no longer as likely.)

As of 7.0.5, the default behavior will be to attempt to match the address with or without the subaddress. If there&#x27;s a match, then the subaddress will be transferred to any rewritten address. This behavior may be explicitly specified by setting the    channel option (the default) on the source  channel. , if set, will match against  subaddresses but disables transfer of the subaddress to the rewritten  address. Finally,   disables special  subaddress handling during the reversal process.

See also:
 * Address reversal
 * subaddressexact Option
 * subaddressrelaxed Option
 * subaddresswild Option
 * Intended side effects of LDAP address reversal