[ILUG] Very elementary question on email

[Robert Sweetnam]

Brendan Kehoe wrote:
> 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?
>>   

Tim,

As Brendan pointed out, your laptop sent it directly.

Also, you have a static IP address from eircom which the domain name
gayleard.com points to. There is also an MX record (Mail Exchanger)
record pointing to that address too but you seem to be blocking incoming
connections to port 25.

Put simply, an MX record tells other e-mail servers the IP address of an
e-mail server configured to handle mail for a particular domain.

Your e-mail appears to be coming from murphy.ie which is not a domain
registered to you or your IP address.  By you using murphy.ie
inadvertently you run the risk of some of your mail falling foul of some
spam filters as they could appear to be spoofed because murphy.ie does
not point to your IP address.

To save any hassle either use smtp.eircom.net as your outgoing server or
change the domain name on your laptop and/or other computers to
gayleard.com

Regards
Robert