Google marks my mail as spam

Question

After SMTPAUTH impairment (we work for restore server and we have done well, as we aren't no more onto blacklists since weeks) we noticed that mails coming from our mail server, are tagged as spam.

I've read some post about (this, for instance) and I've installed,configured and run OpenDKIM (DKIM signature is going well) and SPF aswell. I've also revers dns / ptr available.

When I open mail from google and use "show original", all seems to be good:

Delivered-To: [e-mail]
Received: by 10.50.242.40 with
    SMTP id wn8csp83371igc;
    Mon, 5 Aug 2013 05:55:48 -0700 (PDT)
X-Received: by 10.15.95.4 with SMTP id bc4mr16728809eeb.40.1375707347864;
    Mon, 05 Aug 2013 05:55:47 -0700 (PDT)
Return-Path: <[e-mail]>
Received: from mailservername.mydomain.net
    (mailservername.mydomain.net. [xx.xxx.xx.xxx])
    by mx.google.com with ESMTP id v1si18439718eel.46.2013.08.05.05.55.47
    for <[e-mail]>;
    Mon, 05 Aug 2013 05:55:47 -0700 (PDT)
Received-SPF: pass (google.com: best guess record for domain of [e-mail]
    designates xx.xxx.xx.xxx as permitted sender) client-ip=xx.xxx.xx.xxx;
    Authentication-Results: mx.google.com;
    spf=pass (google.com: best guess record for domain of [e-mail] designates xx.xxx.xx.xxx as permitted sender)
    smtp.mail=[e-mail];
    dkim=pass header.i=@mydomain.net
Received: from [127.0.0.1] (host151-129-static.224-95-b.business.telecomitalia.it
    [95.224.129.151])   by mailservername.mydomain.net (Postfix) with ESMTP
    id D650D4F002F  for <[e-mail]>; Mon,  5 Aug 2013
    14:55:46 +0200 (CEST)
DKIM-Signature: v=1; a=rsa-sha256;
    c=relaxed/simple; d=mydomain.net;   s=default; t=1375707347;
    bh=2bFxKLJuvRxp4hjsyRh0w3NWCXRIIv9QmaY8btqc0zs=;
    h=Message-ID:Date:From:MIME-Version:To:Subject:Content-Type;
    b=1YHHxvq4A86cfsr8ORhefbMq7Ib31qpJvX8OMZYSVJd931zfhfGDEP59Yt+ncGZDF     
    bjT5swmVAj85/5ZzRCsUUO3VaeHYNZqis2Fe9ND6r/5n+xmP8SbcNyNBJmW378Wphp  
    vhGYdVOhfvXHMvF1yY30iPtE7W+wMHihmZXbDBEc=
Message-ID:
    <[e-mail]>
Date: Mon, 05 Aug 2013 14:55:46 +0200
From: Samuele Lilli <[e-mail]>
User-Agent: Mozilla/5.0
    (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130620 Thunderbird/17.0.7
MIME-Version: 1.0
To: [e-mail]
Subject: spf ?
Content-Type: multipart/alternative; 
    boundary="------------060004010506040409020002"
X-Antivirus: avast!
    (VPS 130804-1, 04/08/2013), Outbound message
X-Antivirus-Status: Clean

This is a multi-part message in MIME format.
--------------060004010506040409020002
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Content-Transfer-Encoding: 8bit
[....]

What can I do to escape this situation?

PS.: I've "obscured" some info for privacy reason

Answer 1

There's a lot of things you should check, so you've quite a bit of legwork to do here. If you're sending the same thing to a large mailing list, you might find it less work to simply sign up with a provider like MailChimp or Campaign Monitor. If you're providing email services for end users at a company for example then it's probably easier to go with a hosted solution like Google Apps or Office 365. If you're sending out confirmation emails etc to individual users then you'll probably need your own mail server.

I noticed you've got a hostname in there which looks like a standard business DSL line (telecomitalia). Nothing inherently wrong with that, but you might find some email providers block huge swathes of IP address space around home/business DSL addresses. I once saw a bunch of ex-C&W business IPs blocked because they were being shared by Virgin's home DSL connections.

Apart from that, you need to work through a lot of generic checks.

Here's a good guide on stackoverflow: https://stackoverflow.com/questions/371/

Here's gmail's own advice: https://support.google.com/mail/answer/81126

and hotmail's: http://mail.live.com/mail/troubleshooting.aspx