On 6/20/22 9:59 PM, Tomasz Rola wrote: > As you might know, when the target does not receive email, sender > will try to send it to backup receiver(s), here: That's the idea. At least in an ideal world. Sadly, I've experienced too many ... less than ideal installations. > ;; ANSWER SECTION: > classiccmp.org. 1799 IN MX 10 mx2.ezwind.net. > classiccmp.org. 1799 IN MX 10 mx1.ezwind.net. Those are actually two equal weight peer MXs. There's nothing differentiating one as primary and backup. The "10" would need to be different between the two records. > I infer that the actual date when email will get dumped to /dev/null > depends on settings of relevant mail servers (MTAs) - either sending one > or backup receiver. In an ideal world, messages would never be dumped to /dev/null. Per RFC -- the bible of interoperability on the Internet -- messages should never be lost. Instead, such ultimate undeliverables situations should be reported to the (purported) sender. > If there is a way to get those value remotely by talking to the server, > I have not yet dug it up, nor looked. I'm not aware of anything in the SMTP protocol that is applicable for getting such information. Sometimes it can be inferred by observing behavior. I did receive such a Delivery Status Notification (a.k.a. DSN) from mx1.ezwind.net five days after I sent a message to cctalk. > I assume it might be about two weeks in case of classiccmp and each > email author should be notified when his email fails to reach a > recipient. So, we will see (experiment by doing nothing...), Yep. Hence "inferred by observing". ;-) -- Grant. . . . unix || die