On Monday 20 May 2002 20:34, Tim Churches wrote: > OK, sorry, I missed that last part: > > > It has total control of who it talks > > > to and what path it uses to transfer mail.
This is important... _total_ > a) If Dr A sends a message to Dr C via Dr B's mail server, Dr A probably > doesn't want Dr B to be able to read the message to Dr C So don't do that! > b) How will these special purpose routing tables be maintained? Easy > when there are > only 10 mail servers, not so when there are 1,000 or 10,000. DNS SMTP is used in two ways. Routinely. Small dial-up systems tend to use SMTP - relay, where they pass on tehir messages to a smarthost which then relays them... Larger always-on systems, or mine if I flick the switch, usually use Direct SMTP In this case they look up the Mail eXchanger record in DNS (which could be a collegiate DNS, or a private one, it doesn't have to be public) for the recipient, and connect to it and pass the mail file to it. I think the story about having no control over where messages go is actually FUD, probably spread about by X.400 vendors or users, since the controlson path for SMTP and X.400 are not that different - IE if you are using a chain (not obvious since your smarthost probably spends all day doing Direct SMTP to destination mailservers) the route on from each machine is dependent on the good judgement of the owners and administrators of that machine, and why owuld the previous link choose them if it didn't know and trust them. It isn't random. -- From one of the Linux desktops of Dr Adrian Midgley http://www.defoam.net/
