> It made sense at a time when availability wasn't guaranteed. It still isn't guaranteed. There's any number of reasons two MTAs can't talk to one another. The

> It made sense at a time when availability wasn't guaranteed. It still isn't guaranteed. There's any number of reasons two MTAs can't talk to one another. Then there's more reasons an MTA can't talk to an MDA. > Rather than that server having to push all mail content around, it could hold the messages and post notifications to the destination, then release only after delivery has been accepted. IIRC this was one of the ideas behind Internet Mail 2000[0]. The open questions on that page are actually pretty good arguments against such a system. Not that e-mail is perfect but an open message sending system has a lot of important details to get right to work properly. [0] http://cr.yp.to/im2000.html http://cr.yp.to/im2000.html