Do you email Gmail?
I am sure you or at least your server does.
As the world’s largest provider of free email services, you need reliable email delivery to Gmail. If not, you may lose both customers and revenue.
Before you tout, “I am not a spammer.” Remember:
Gmail blacklists servers that send spam or behave like a spammer.
If you find Gmail has blocked your server, then someone, something or somehow you’ve done something that looks like spamming in the eyes of Google.
Fortunately, I am getting ready to tell you my tips on how to remove your IP from the Gmail Blacklist.
Are You a Server Admin?
If you are not a server administrator, then the tips below may not help you much. These tips are for system and email administrators who have access to their email servers logs.
Without direct access to the logs, there’s not a lot you can do as an end user — except pester your system administrator.
If you are an admin, then read on.
You may be tempted to jump to the bottom of the post where I have the URL for the Gmail blacklist removal form. Don’t!
If you don’t fix the issue, you will just get re-listed – perhaps permanently.
Blacklisted or Spam?
Commonly, people confuse email going into Gmail’s spam folder with being blacklisted. These are not the same.
If you are blacklisted, your email will be rejected with a 421 or 550 SMTP error. You can spot this in your email server’s logs:
Example of a 550 Error:
Remote_host_said:_550-5.7.1 Our_system_has_detected_an_unusual_rate_of unsolicited_mail_originating_from_your_IP_address. _To_protect_our users_from_spam,_mail_sent_from_your_IP_address_has_been_blocked. Please_visit_http://www.google.com/mail/help/bulk_mail.html _to_review_our_Bulk_Email_Senders_Guidelines
Example of a 412 Error:
421-4.7.0 unsolicited mail originating from your IP address. To protect our\n421-4.7.0users from spam, mail sent from your IP address has been temporarily\n4 21-4.7.0 rate limited. Please visit http://www.google.com/mail/help/bulk_mail.\n421 4.7.0 html to review our Bulk Email Senders Guidelines. l41si55243084eef.158 - gsmtp
If you see either of these errors, you will have email delivery errors to Gmail.
Deciphering Gmail SMTP Errors
The SMTP errors that Gmail provides are key to mapping your path to getting off of Gmail’s blacklist.
For email delivery, the two main error codes are 421 and 550 errors.
421 errors are often temporary blocks. Most email servers will attempt to resend the email if they get a 421 error. If you quickly correct a spam or email flood issue, these blocks may resolve automatically. Left unchecked, Google may decide to block your email entirely.
550 errors are permanent failures. If you scan your logs for 550 errors from Gmail, they will often include links and additional information.
If you have 550 errors, you will likely need to take action before Gmail will remove your server IP address.
Gmail does not publicly disclose their email filtering policies, but a key feature used by almost all email filtering systems is sender reputation. Sender reputation attempts to place a score on how likely email originating from your server is going to be spam. Scoring methods are complex. While I don’t know Gmail’s specific methods, most systems take into account:
- Email Volume
- Complaint Rates
- Spam Trap Hits
- Changes in Email Volume
- History of IP Address
- Bounce rates
- Email Sent to Unknown Users
- Total Email Volume
- IP Neighborhood
All of these factors go into determining your sender score. I recommend you always check your sender score before doing any blacklist removal requests. Many ISPs rely on sender score from ReturnPath, so I always check it there. Even if Google does not use this directly, a low score there likely signals broader email delivery issues.
Top 4 Ways to Get Blacklisted
As part of our server support packages, we help a number of businesses get remove their IP from Gmail’s blacklist.
In our investigations, the most common reasons why Gmail blacklists your server are:
- Compromised user account used to send spam.
- Web application exploit used to send spam.
- Bulk emailing from mailing lists, newsletters, forums & blogs (even if they are opt-in).
- Bulk forwarding of email to Gmail.
The four items account for about 95% of all spam cases we investigate
The first two are security issues. Poor passwords and outdated web applications are hacker favorites. In either case, a compromise can mean 10,000′s of emails get sent to Gmail in a matter of hours. Such a breach will certainly land your server’s IP on their blacklist.
Another source of blacklisting is notices from forums, blogs or newsletters. Even if the person subscribed to the email and you provide opt-out information, Gmail may still flag your email as spam.
Lastly, forwarding large amounts of email to Gmail can trigger a blacklisting. We see this when people forward email blindly to Gmail. They then mark the email as spam. The result is that your server’s sending reputation is penalized since it was the one that last sent the email. This is a commonly overlooked reason for blacklist inclusion.
Do the DNS Double Check
If your DNS is not correct, you may have email delivery issues — even if you found no malicious activity.
DNS goes beyond just having a MX record. You need to check and verify the following:
- Sending server’s hostname resolves
- Reverse DNS (PTR) for your email server
- SPF, if present, is correct
- DKIM, if used, is correct
- Domains used in email headers resolve
Requesting Blacklist Removal
Just so you know … Google does not want you to contact them.
Their forms are buried behind a series our questions that typically lead nowhere. Most of the time you will start with Gmail’s “My domain is having delivery problems with Gmail” form. As you answer the questions, you will typically end up in a dead-end.
However, with the right sequence of answers, you can eventually wind your way to:
This is where the action happens. Complete the form in detail but do not be overly verbose.
Once submitted, you can expect it to take 3-7 days to process. Often, you will not hear back from Gmail. Your email will simply start flowing again – provided you fixed the reason you were blacklisted in the first place.
Sometimes you have a lot of email – legitimate email – to send. Google does not clearly define what is bulk email. Typically, you will see an SMTP error code in the 400 series, such as:
421, "4.7.0", Our system has detected an unusual rate of unsolicited mail originating from your IP address. To protect our users from spam, mail sent from your IP address has been temporarily blocked. Review our Bulk Email Senders Guidelines.
If all of this seems too much, then we can help.
We provide blacklist removal services for people using CentOS, Red Hat, Plesk and cPanel servers. Most cases require a Level 3 Support Package.
While we cannot guarantee results, we are successful in more than 95% of cases (100% successful so far in 2014).
Note that we have no formal relationship with Google or maintain their blacklist. We just know how to fix email problems correctly.
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