On 02/12/2010, at 23:08, Stan Hoeppner wrote: > Martin Kellermann put forth on 12/2/2010 6:08 AM: > >> and there's a 5 sec. delay ... seems way too long to me for just >> checking the recipient...!? > > That delay should be no longer than what a typical delivery to the > Exchange server would be. Since no message is sent, it should be > shorter by quite a bit. I would guess the delay is within the Exchange > server, not Postfix, so you may need to do some sleuthing on the Exch > server to see what it causing the delay.
A testing tool like 'swaks' is great for testing RAV and other SMTP transactions; http://jetmore.org/john/code/swaks/ >> PS: should unverified_recipient_reject_code set to 450 or 550 ? > > You should probably leave this at the defaults. As I understand it, the > default configuration will return a 5xx for "unknown user" and a 4xx if > the query fails, due to network, etc. The default is '450' for both unknown users and transient errors, see; http://www.postfix.org/postconf.5.html#unverified_recipient_reject_code From the same page: "The unverified_recipient_reject_code parameter specifies the numerical response code when an address is known to bounce (default: 450, change into 550 when you are confident that it is safe to do so)". We also found it very handy to set up our 'notify_classes' parameter, so the postmaster (or any other user you configure) gets a transcript of the SMTP session when Postfix rejects mail. Note however that this adds load and can generate a large volume of messages to the postmaster. It works for us at our current volume, YMMV. Lastly, you may want to set a value for 'unverified_recipient_reject_reason' if you don't want to share the details of the backend server, such as hostname and/or IP address, with the outside world. Cya, Jona
