What so wrong about my mail headers? /a newbie question/

GSMD · 05-30-2006, 05:34 AM

I've got a mailserver (postfix + dovectot) installed behind nat.
There is no problem receiving mail but outcoming mail gets blocked time to time.
Could you please give a hint what so wrong in the headers of outgoing e-mails?

|the domain names, e-mails and ips are changed for security reasons, mydomain.ay is an internal domain name|

Code:

Message-ID: <2030.10.1.0.7.1148983346.squirrel@webmail.mydomain.com.ua>
Date: Tue, 30 May 2006 13:02:26 +0300 (EEST)
Subject: lol
From: user@mydomain.com.ua
To: samplemail@gmx.net
User-Agent: SquirrelMail/1.5.1
MIME-Version: 1.0
Content-Type: text/plain;charset=koi8-r
Content-Transfer-Encoding: 8bit

Thank you.

peter_robb · 05-30-2006, 07:57 AM

Show an example from the Postfix logs showing a reject..

GSMD · 05-30-2006, 08:19 AM

It's not rejected but put to the Spam folder on the client side.
That's the reason I think there is possibly smth wrong with headers.

peter_robb · 05-30-2006, 08:32 AM

Most likely coz your MTA helo is only a number, rather than a fqdn.

It has tagged the mail as NOT SPAM so another filter is operating.

Try adding [ ] around your helo number to make it [62.64.105.99]

GSMD · 05-30-2006, 09:16 AM

Thank you, I'll try that.
Is that helo important at all so that I could safely delete it?
Is it possible with Postfix to remove Received: from blocks harmlessly (as gmail does)?

Thanks for such a quick responses!

peter_robb · 05-30-2006, 09:43 AM

The helo is vital for anti-spam software..
If you don't have it, your chances of being rejected are much greater.

It is a part of the email rfc and necessary, as are the Received Headers.
They are added as mail comes into an MTA server, so you don't get to control them.

If you add a content filter to your Postfix, eg amavisd-new, you can strip the local parts so that only the amavis Received header is added by Postfix.
This is against the rfc, but necessary to avoid giving away your local net info.

GSMD · 05-30-2006, 10:02 AM

Thank you. Perfectly clear.
One last question: should i put mail.domain.com. or just domain.com. to helo? Both domains share the same ip.

P.S. Mail RFC can be found at http://www.lemis.com/email/email-rfc.html

peter_robb · 05-30-2006, 10:09 AM

You need to have something that can resolve correctly..
The helo is the fqdn of the pc connecting, so the reverse dns must work as well.

The headers you posted show that your ip number doesn't resolve to a fqdn, so just use the ip address inside [ ]

GSMD · 05-30-2006, 10:13 AM

This will be fixed. Thaks again.