email header question

[Red Squirrel]

I'm trying to double check that my local email server is properly formatting emails so that spam filters do not think it is bulk mail, lot of them check for certain things like if the DNS is resolvable etc. i sent an email to my gmail which looks like this:


Delivered-To: *user*@gmail.com
Received: by 10.82.115.2 with SMTP id n2cs77592buc;
Thu, 3 May 2007 12:23:29 -0700 (PDT)
Received: by 10.35.62.19 with SMTP id p19mr3808047pyk.1178220209031;
Thu, 03 May 2007 12:23:29 -0700 (PDT)
Return-Path: <*me*@*mydomain.com*>
Received: from *external-dnsname* (NTL208H101-78-212.nt.net [208.101.78.212])
by mx.google.com with ESMTP id f57si4878554pyh.2007.05.03.12.23.28;
Thu, 03 May 2007 12:23:29 -0700 (PDT)
Received-SPF: neutral (google.com: 208.101.78.212 is neither permitted nor denied by best

guess record for domain of *me*@*mydomain.com*)
Received: from [10.1.1.20] (unknown [10.1.1.20])
by *external-dnsname* (Postfix) with ESMTP id 48C8114CFE1
for <*user*@gmail.com>; Thu, 3 May 2007 15:23:27 -0400 (EDT)
Message-ID: <463A4424.6010601@iceteks.com>
Date: Thu, 03 May 2007 15:20:52 -0500
From: Ryan Auclair <*me*@*mydomain.com*>
User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923)
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: *user*@gmail.com
Subject: test
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit


The external-dnsname is a static host name that updates with my external IP address and they match. me @ mydomain is my actual email which is hosted on my webhost space but when I send mail it comes from my local SMTP server. It's how I have things setup for various reasons.

The only thing I notice in the email header is that it shows my local machine's IP address, would that be an issue for a spam filter? That IP is the machine it was sent from, not the server (server is .10, but in the case of that header, it's my external IP). This SMTP server has no open ports to public.

I'm using postfix. Anything in that header that's not right, or does that look ok? My dad says he sends email to people and they don't receive it, but I've done my own tests and mail gets sent fine. He got a few "unknown user" bounces that came from the destination email's SMTP server. Just not sure if the issue is at my end or not and wanted to rule that out, or if it is my end, fix it.

 

[Nothinman]

A single header problem shouldn't be an issue since most SPAM filters either use RBLs and/or point sytems like SpamAssassin. And it's fairly easy to run your mail through SpamAssassin yourself and see what kind of points you get. Now if you're having your own postfix server deliver the mail directly instead of relaying through your ISP's mail server or another server not on a consumer range then that might be the issue since a lot of places now don't accept mail from known consumer IP ranges.

 

[Red Squirrel]

Hmm so I should maybe relay it then. I think I remember seeing a postfix option for that.

Only thing, I have several email domains on my local server, so lets say I relay through example.com and the from email is @somethingelse.com would that cause issues?

 

[Nothinman]

It depends on how strict the machine doing the relay is but I doubt it'll matter. Email headers have no authentication and are so easily spoofed that it's insane to try and verify most of them.

 

[spyordie007]

Originally posted by: Nothinman
It depends on how strict the machine doing the relay is but I doubt it'll matter. Email headers have no authentication and are so easily spoofed that it's insane to try and verify most of them.

If SPF records have been configured correctly you can be reasonably certain that emails are coming from where they say they are coming. Of course that would require all those server admins to create the proper records on their DNS servers 😉