They are doing the Right Thing and not being an open relay. Basically the server says *one* of the persons involved has to be
In both cases one is always a local user. But only in one case is authentication required.
Without authentication, if you are sending, the mail server can't tell a local from a remote user. (It can always tell for receiving: it just checks its own delivery tables.)
(There are ways around this. But they are fairly easy to spoof if the mail server is accessible from the internet, and do not work for roaming 'local' users or static IP addresses (well, static IPs could be used, with a lot of extra work). Authenication is easier to set up and harder to spoof.)
I could spam all the local users as [EMAIL PROTECTED] all day long without any knowledge of there settings. So I guess, why not authenticate both ways? Just a pondering, no big deal since they'd have to get a scirpt on the server and that'd make them trackable pretty quick.
For remote to local: authenticate how? You don't want to block mail coming in from random domains (since you don't know which are spam domains and which aren't), so you have to let random people send you email. Otherwise the only email you can handle is local to local, and that just isn't very useful. (Note: joemama is probably a registered, legit, and paid-in-full user of remotespamville.com , so you can't say people who aren't from that domain. He *is* from that domain.)
And now we are well into anti-spam theology. (There have been several complete systems proposed to handle the 'authenticated guest' problem here, none currently is in use.) And out of Perl. ;-)
Daniel T. Staal
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