I was thinking about something I wrote here a couple of days ago. A 450 response from my server being delivered to the original sender is a mistake - isn't it? Everything I have read to date seems to indicate that 4xx codes are temporary conditions between SMTP endpoints. But as I am new to this I started to wondering if I was correct in asserting that such response messages should not as a rule get back to the sender.
I came across this when I got a complaint that I had "bounced" somebodies email with a 450 indicating the message was being delayed due to greylisting. The sender received the following message in their inbox "450 4.2.0 <he...@mumble.com>: Recipient address rejected: Greylisted, see http://postgrey.schweikert.ch/help/mumble.com.html; from=<mumble> to=<he...@mumble.com> proto=ESMTP helo=<smtp12.bis.na.blackberry.com>." which seemed odd to me. As a secondary question, does this response give out too much information about how we handle email. TIA JLA
