Delivery Notification corrupts RCPT TO: with no CRLF Invalid Syntax

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When setting delivery notifications it seems the email RCPT TO is corrupted or invalid. I am using hMail server and it had been working with an alternative SMTP client.

When selecting to add Delivery Failure Notification it seems it is corrupting the reply address

"SMTPD" 200544 508 "2014-11-17 20:02:32.663" "127.0.0.1" "RECEIVED: RCPT TO:anything@emessage.com NOTIFY=FAILURE"
"SMTPD" 200544 508 "2014-11-17 20:02:32.665" "127.0.0.1" "SENT: 550 Invalid syntax. Syntax should be RCPT TO:[crlf]"

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1 Answer

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Best answer

Mail.dll sends line endings correctly, all commands are ended with CRLF.

This is handled on a different (lower) library level, so changing Smtp.Configuration.DeliveryNotification doesn't affect that.

The problem is not with the missing crlf, hMailServer simply doesn't recognize NOTIFY parameter.

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