7 messages in net.sourceforge.lists.courier-users[courier-users] Re: Private email dom...
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Jon NelsonNov 20, 2003 7:26 pm 
Gerardo GregoryNov 21, 2003 8:45 am 
Jeff PotterNov 21, 2003 11:45 am 
Gerardo GregoryNov 21, 2003 12:14 pm 
Sam VarshavchikNov 21, 2003 3:12 pm 
Julian MehnleNov 21, 2003 3:54 pm 
Jeff JansenNov 21, 2003 10:34 pm 
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Subject:[courier-users] Re: Private email domain??????Actions...
From:Sam Varshavchik (mrs@courier-mta.com)
Date:Nov 21, 2003 3:12:41 pm
List:net.sourceforge.lists.courier-users

Gerardo Gregory writes:

Been tasked with setting up a virtualdomain that is private for internal corporate communication.

Currently I have Courier-MTA, maildrop for local delivery, PAM auth, and some virtul domains already setup using userdb.

The domain I am asked to setup needs to only be able to send / receive mail from within that domain. How do I create this type of restrictions?

A “domain” cannot send/receive mail from within that domain no more than a last name can talk to another last name.

A “domain” is conceptually the same as a person's last name. Last names do not talk to each other. People with last names talk to other people. Similarly, domains don't send messages; it's mail clients who send messages. Any mail client can be configured to use any E-mail address, and any domain that the user wishes to use.

You can no more restrict a “domain” from sending mail than restricting a last name from talking to each other.

There's nothing a mail server can do to physically prevent a given mail client from using any return address. The theoretically closest that comes to that is requiring all mail clients to use authentication, and restricting the From: header to match the authenticated sender's identity; but that in no way stops the mail client from being configured to use a different mail server.