I have just finished reading a bunch of stuff on UCE and the "effects" of the various parameters associated with the smtpd_*_restrictions, and I am now somewhat confused as two of the authors I have been reading state that if a message receives an "OK" from any check then all further checks are abandoned. This does not make any sense and I am fairly sure that they got it backward but both of them are adamant!
This is/was my understanding, from reading the documentation and elsewhere.If a restriction check was successful (i.e., OK/DUNNO) then postfix moves on to the next check, if on the other hand the check was unsuccessful then the message is dropped and no further checks are done. e.g., if the following is the sequence in main.cf : smtpd_xxx_restrictions = reject_non_fdqn_hostname, reject_unknown_recipient_domain, reject_non_fdqn_recipient, (permit) then if the hostname is a fdqn, then postfix continues on to unknown_recipient, and if that is OK moves on to the non-fdqn_recipient ... until it runs out of check at which point he default (usually permit) is exercised. if on the other hand the hostname is _not_ a fdqn the message is dropped and no further checks are performed under the xxx restrictions. Furthermore, if a message is dropped at say the client phase then checks in helo and subsequent phases are not performed. TIA JLA
