[ILUG] Very elementary question on email

[Brendan Kehoe]

Timothy Murphy wrote:
> But my query is - why is email working OK,
> despite the fact that I didn't do anything to sendmail.mc (or .cf)?
> How does the email know where to go?
>   

I'm guessing that it's performing direct delivery itself.  It looks up
your destination, figures out where it should go, and does the deed itself.

The headers

Received: from elizabeth.murphy.ie (unknown [86.43.71.228])
	by morrigan.tuatha.org (Postfix) with ESMTP id AE72A4CC1CD
	for <ilug at linux.ie>; Wed, 19 Sep 2007 19:08:22 +0100 (IST)
Received: from elizabeth.murphy.ie (localhost.localdomain [127.0.0.1])
	by elizabeth.murphy.ie (8.14.1/8.14.1) with ESMTP id l8JHlgv8011278
	for <ilug at linux.ie>; Wed, 19 Sep 2007 18:47:42 +0100
Received: from localhost (localhost [[UNIX: localhost]])
	by elizabeth.murphy.ie (8.14.1/8.14.1/Submit) id l8JHlfFT011277
	for ilug at linux.ie; Wed, 19 Sep 2007 18:47:41 +0100
X-Authentication-Warning: elizabeth.murphy.ie: tim set sender to
	gayleard at eircom.net using -f


show that your machine elizabeth.murphy.ie directly connected to the
tuatha.org server to send your message.  Thus sendmail isn't set up with
any sort of relay, and instead performs the SMTP connection after doing
the requisite lookups.

> Is it up my ISP (Sir Anthony) to forward it correctly?
>   

Nope.

> I've always gone to great trouble to specify the mail server
> (in my case smtp.eircom.net)
> but it seems that is unnecessary?
>   

The only catch is if your mail couldn't get delivered---if you don't
keep that machine on all the time, running that OS, or whatever, then
there's no certainty that the queue will be run regularly to keep trying
til it ends up being delivered.

To make sendmail use a specific outgoing mail server, check out the
instructions at

    http://www.mail-abuse.com/an_rteoutgoing.html


Hope this helps,
B