DeliveryNotificationOptions won't work on gmail and hotmail

I am using SmtpClient to send a message through a gmail account, I set DeliveryNotificationOptions to DeliveryNotificationOptions.O开发者_开发问答nSuccess, the message sent ok, but there is no delivery notifiacton. I also tried hotmail, still no delivery notification. However the same code works fine on outlook exchange server.

any ideas? Cheers Harry

There is no gaurantee that any mail server will support this option, you cannot count on it at all. If hotmail and gmail respected this can you imaging how useful it would be to spammers.

I don't know about Hotmail, but Gmail definitely doesn't support delivery notifications:

Read receipts in Gmail