Re: [gentoo-server] email server concept: what's mail delivery agent

[Drake Wyrm]

At 2004-06-02T19:44:44+0800, Zhang Weiwu <zhangweiwu@××××××.com> wrote:
> 1. Moden mail servers don't often do mail forwarding. So upon receiving
> an email, it will always be 'local delievery'.;

Not quite. Most mail servers have the capability to perform forwarding,
but it must be explicitly enabled. Otherwise, you run the risk of
letting anybody relay mail through your server. However, upon receiving
an email from the local machine (or any other authorized host) a
properly configured mail transfer agent will forward the email toward
its final destination.

> 2. Documents often mention 'delivery agent' and 'maildir', it seems
> 'delivery agent' is not a standalone package, there is a delievery agent
> in postfix package, and there is also one in cyrus package, I can choose
> to use the delivery agent (postfix's or cyrus')

You could also hand everything off to procmail, which is a standalone
delivery agent with filtering capability. As you noted, transfer agents
typically have delivery agent capability and the capability to hand
email off to an external delivery agent. 

> I feel messed up reading all the documents, now I am afraid I got severl
> concepts completely wrong so I just write what I think plainly and hope
> someone kindly come out and say to me "hey, you got xxx wrong here", and
> I'll be thankful:)

Unfortunately, I can't really say "you got xxx wrong here", because you
seem to be mostly right.

-- 
Batou: Hey, Major... You ever hear of "human rights"?
Kusanagi: I understand the concept, but I've never seen it in action.
  --Ghost in the Shell