1Postfix DSN support implementation notes 2======================================== 3 4In delivery status reports, Postfix now properly reports remote 5LMTP/SMTP server replies with Diagnostic-Type: SMTP, with the 6Diagnostic-Code: equal to the server reply, and with Remote-MTA: 7equal to the name of the remote MTA. 8 9Of course Postfix still produces the same "informal" error descriptions 10that it produced before (for example, the error text that appears 11in the first section of a bounce report). 12 13Other error reports are not in the form of SMTP-style replies. 14 15- The Postfix LMTP/SMTP client generates Diagnostic-Type: X-Postfix 16for locally generated errors (host not found, connection timed out 17etc.). It generates Diagnostic-Type: SMTP only for replies from 18an SMTP server. 19 20- The queue manager generates Diagnostic-Type: X-Postfix for errors 21that it detects. It also receives error information from delivery 22agents and reports that information unmodified when it decides to 23"temporarily suspend" a delivery channel. 24 25- The "pipe to command" code in local(8) and pipe(8) produces 26Diagnostic-Type: X-UNIX, and Diagnostic-Code: text that is taken 27from /usr/include/sysexits.h or from the command output. 28 29- The code that delivers to mailbox produces Diagnostic-Type: 30X-Postfix and Diagnostic-Code: text that is the same good old 31Postfix error message that we are already familiar with. Typically 32these are errno-style reports about locking a file or appending a 33file. 34