I'm getting very weird results here. When my server sends an email to my @hotmail or @gmail account, it's marked as spam. When I send email through my server from Outlook to @hotmail, it doesn't get marked as spam, but it still gets marked as spam in gmail. They seem to get through fine on Yahoo though.

My servers hostname A record points to an IP address whose PTR record points back to the same domain name. The TXT record has a SPF record in it to allow email to be sent from that servers IP.

I moved from a VPS to a Dedicated server when this started to happen. From what I can see, the email headers are identical. Here's one of my email headers that gmail marks as spam. Some fields were repalced.

MYGMAILACCOUNT is the email address of the account the email was addressed to.
USER is the name of the account on the system it was sent from
HOSTNAME is the servers FQDN
IPADDR is the IP Address of the Hostname
MYDOMAIN is my domain name

Received: by with SMTP id f18cs263483vck;
        Sat, 27 Feb 2010 23:58:02 -0800 (PST)
Received: by with SMTP id 4mr3886702ybp.110.1267343881628;
        Sat, 27 Feb 2010 23:58:01 -0800 (PST)
Return-Path: <USER@HOSTNAME>
        by mx.google.com with ESMTP id 17si4604419yxe.134.2010.;
        Sat, 27 Feb 2010 23:58:01 -0800 (PST)
Received-SPF: pass (google.com: best guess record for domain of USER@HOSTNAME designates IPADDR as permitted sender) client-ip=IPADDR;
Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of USER@HOSTNAME designates IPADDR as permitted sender) smtp.mail=USER@HOSTNAME
Received: from USER by HOSTNAME with local (Exim 4.69)
    (envelope-from <USER@HOSTNAME>)
    id 1Nle2K-0000t8-Bd
    for MYGMAILACCOUNT; Sun, 28 Feb 2010 02:57:36 -0500
Subject: [Email Subject]
MIME-Version: 1.0
Content-type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: webmaster@MYDOMAIN
Message-Id: <E1Nle2K-0000t8-Bd@HOSTNAME>
Date: Sun, 28 Feb 2010 02:57:36 -0500
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - HOSTNAME
X-AntiAbuse: Original Domain - gmail.com
X-AntiAbuse: Originator/Caller UID/GID - [503 500] / [47 12]
X-AntiAbuse: Sender Address Domain - HOSTNAME

Anyone have any ideas as to why all mail leaving my server gets marked as spam?

EDIT: I already used http://www.mxtoolbox.com/SuperTool.aspx to check if my servers IP's are blacklisted and they are in fact not. That's what I thought at first, but it isn't the case.

Update Mar 1, 2010 I received the following email from Microsoft

Thank you for writing to Windows Live Hotmail Domain Support. My name is ******* and I will be assisting you today.

We have identified that messages from your IP are being filtered based on the recommendations of the SmartScreen filter. This is the spam filtering technology developed and operated by Microsoft and is built around the technology of machine learning. It learns to recognize what is and isn't spam. In short, we filter incoming emails that look like spam. I am not able to go into any specific details about what these filters specifically entail, as this would render them useless.

E-mails from IPs are filtered based upon a combination of IP reputation and the content of individual emails. The reputation of an IP is influenced by a number of factors. Among these factors, which you as a sender can control, are:

  • The IP's Junk Mail Reporting complaint rate
  • The frequency and volume in which email is sent
  • The number of spam trap account hits
  • The RCPT success rate

So I'm guessing it has to do with the fact that I got an IP address with little or no history in sending email. I've confirmed that I'm not on any blacklists. I'm guessing it's one of those things that will work itself out in a month or so. I'll post when I hear more.

  • 2
    Received: from HOSTNAME (HOSTNAME [IPADDR]) This is the critical part, please resubmit your question without this data occluded. Feb 28, 2010 at 9:08

9 Answers 9


Modern major mail services score spamminess based on multiple reputation factors, if available.

If the only factor is your IP and you don't mail often, this might be "the reputation of the /24 my IP is in". If you mail a lot, you might get your own reputation.

The easiest way to get reputation which "drowns out" the IP reputation of your netblock is to set up DKIM. Send your mails signed. This will establish a per-domain reputation, instead of per-IP reputation, and provides more signal to the automated scoring systems.

The more you work to help the recipients of your email figure out who you are and how trustworthy you are, the more signals they have to work with and the better a job the automated systems can do in deciding that you're legitimate, unlike whoever else bought a virtual machine in the same netblock, pumped out spam and then left, bills to hosting service unpaid and everyone else's reputation tarnished.

[some years later]: I wrote a blog post a couple of years back, walking through a lot of the steps needed to be able to more reliably send to large mail providers: https://bridge.grumpy-troll.org/2020/07/small-mailserver-bcp/

  • 2
    After getting in contact with Microsoft and Google, I have learned that this was in fact the case. Mar 18, 2010 at 3:20

As stated by Sickin, look for popular blacklists if you server is listed @ http://www.mxtoolbox.com/blacklists.aspx

If your IP is listed, have it removed by visiting their websites.

Optionnaly, make sure you have a valid reverse DNS on the IP address. Note that this could take several days to take place on GMail and Live.


Are you running your email server out of your home? With, say, a cable modem/DSL connection? If so, they're probably getting tagged as spam because your IP address is known as a DHCP address for an ISP.


Chances are you're not an ISP, and you don't have a static block of addresses that belong to you, so some (many) email services will suspect you're spam just because you have an IP address that is not known good. (Not blacklisted, but not whitelisted, either). You could just as well be a home PC taken over as part of a botnet for all they know.

I'd recommend you contact your ISP about a smarthost - a server they run just to pass your mail through so that it comes from a "known good" mail server. This will do two things. First, it will get you past most of those filters. Second, if you do happen to be hijacked, your ISP will shut down your outgoing mail and let you know about it.

No, whitelisting won't help. You can't keep up with them all, and many won't accept your IP because it is (probably) in a dynamic block. (You could have the same IP for 20 years, but if it's in a dynamic block, it's dynamic. Think about 555-1234...)


Just an idea, this could be do to the fact that you've moved to an IP that has been blacklisted? It is possible.

Regardless it's nearly impossible to get off a blacklist. I suggest moving your server to another IP address, changing the hostname in you CNAME and testing it again, that way you'll know if it was the IP that has been blacklisted and not you hostname.


See if the ip of your new server is on any blacklists, google will find a bunch of things to check like http://www.mxtoolbox.com/blacklists.aspx


Looks similar to the problem I am having. Some good suggestions and answers in my thread: Google marks seemingly perfect emails as spam

Good luck!


Try this Email Server Test. It has some additional content checks in addition to the standard IP/DNS ones and might give you some idea on what is wrong.

  • Everything is green except BATV (Bounce Address Tag Validation) Check which was yellow and said "Email server is not using BATV format while sending out emails. BATV is recommended to ensure that your users do not become a victim of bounce floods." Mar 1, 2010 at 19:09
  • BATV is not an issue that could make your emails go to SPAM folder. The only thing left will be to contact respective postmasters and ask them to Whitelist your IP. Mar 2, 2010 at 11:38

Does any of this help? http://mail.live.com/mail/troubleshooting.aspx


Are you sending email from new IPs?

IPs not previously used to send e-mail typically don’t have any reputation built up in our systems. As a result, e-mails from new IPs are more likely to experience deliverability issues. Once the IP has built a reputation for not sending spam, Windows Live Hotmail will typically allow for a better e-mail delivery experience.

New IPs that are added for domains that are authenticated under existing Sender ID records typically experience the added benefit of inheriting some of the domain’s sending reputation. If the domain has a good sending reputation new IPs may experience a faster ramp up time. A new IP can expect to be fully ramped within a couple of weeks or sooner depending on volume, list accuracy and as long as their junk e-mail complaint rates are kept at a minimum. To update or create your Sender ID record, click here.

Note: In addition, to adding your new IPs to existing Sender ID records, don’t forget to update your Junk E-Mail Reporting Program (JMRP) account with the new IPs as well. To update or set up a JMRP account, click here.

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