Inbox Pros Blog   »   The Only List You Don’t Want to be on This Christmas: The Blacklist

The Only List You Don’t Want to Be on This Christmas: The Blacklist

Author丨Jenna Moye

Little boy mad standing beside a Christmas tree


This might be a refresher for many email marketers but this recap is well worth it and might save you from a long fourth quarter of stress and anxiety- oh, and money too!  It is safe to say that the word, ‘blacklist’, doesn’t sound very appealing. In fact it’s the absolute last place that you, as an email marketer, want to end up as you attempt to push your campaigns out the door in time for the holidays. Black Friday and Cyber Monday are the two busiest shopping days of the entire year and you’re not doing your business or consumers any favors if your they aren’t getting any of your emails, especially during your biggest sales of the year.


What is a Blacklist?

A blacklist is a compilation of IP addresses or domains (depending on the blacklist) that are known to send spam emails. ISPs (Internet Service Providers) have spam filters in place and identify mail based off certain criteria. These addresses are either blocked or routed to the spam folder of your recipient. If it isn’t due to a filter, it can also happen when your emails are marked as spam multiple times. This lets the ISP know that your emails contain spam. Most ISPs have internal blacklists, Though not extensive, they do consist of known spammers that do not send legitimate emails. There are also third-party blacklists that are based on complainers or emails that are consistently hitting spam traps.

Chaet of Ip and domain blacklists


How Do I Get on a Blacklist?

There are various reasons why senders end up on a blacklist. Sometimes they don’t even know they are sending spammy (spam) emails if it’s not visible to them- I’ll explain below. What it also boils down to is senders not implementing email best practices in their sending strategies. Here are  some common ways to end up on a blacklist:


-Email Blasts– The term ‘email blast’ doesn’t sit well with most email marketers. It sounds hurtful, and that’s sometimes exactly what happens- it hurts senders’ reputations. An email blast is the act of sending the same email to your entire database. Fulcrum Tech said it best, based off the the definition of a blast,The next time you’d like to send a vehement outburst” to your email list, think twice. This point alone encompasses many reasons why they are blacklisted. If you are going to send out an email blast, make sure the intended recipients expect communication from you. This means they have specifically opted-in to receive your emails.

Cold emailing might get your email into the inbox the first time, but it’s unlikely to end up there again if the person you are sending to has no idea who you are. This also means refrain, at all costs, from scraping or purchasing third-party lists. If you are sending to a list where they have specifically agreed to receive communication with you, keep your content relevant. If someone hasn’t opened an email from you in 6 months,  consider removing them from your list or starting a re-engagement campaign. It’s just a matter of time before a recipient is going to grow tired of your emails and start marking you as spam.


-Unsubscribe Link– Contrary to what you might believe, an unsubscribe is much better than someone marking you as spam. Not only does it show to the ISP that someone opened your email, but that they also clicked on a link, which shows engagement. Some marketers are sensitive to unsubscribes, but this is much better than the alternative. One of the best ways to not get marked as spam and get an unsubscribe instead is simple- have a clear unsubscribe button. This means make it visible, easily accessible, and do not embed it into any images. That’s not everything though; you need to make sure to honor the subscribers request. The CAN-SPAM Act of 2003 states you must honor unsubscribes within 10 days. Non compliance of this can result in fines of upward to $14,000.


-Large Quantities of Email- Email blasts from a newly set up IP can cause a drop in your  reputation score. Say you just set up a new IP and you’re sending emails to your large database. If you blast a high volume right off the bat, that can definitely affect your sending reputation. Gmail and other major ISPs recommend that once a new IP is set up, to go through an IP warming process. For example, some ISPs prefer you to start with 50-100 emails the first day and then increase that by 1.5 to 2 times everyday afterwards. On the other hand, other ISPs prefer sending to a consistent total for 5 consecutive days and then doubling after that period.


-Content– ISP’s also look at what kind of email you are sending when it comes to subject lines and your content. If you use words like “free” or ‘win” or have special characters like dollar signs and an over usage of exclamation points in your subject lines, people will normally mark those as spam quickly. That said, approximately 47% of people open an email solely based on subject line. Once an email has been opened, you have about 8.25 seconds to capture the reader’s attention with your content before they move on. Next time you are designing an email, don’t underestimate the impact the subject line has.

The recommended text/image ratio is 70:30 as the the email marketing world is moving towards having more image heavy content. Having positive and consistent engagement allows the ISP to provide a bit more leeway to this ratio. One thing to keep in mind is to avoid an all image campaign design. This is common practice among spammers to circumvent text filters that ISPs have in place.An interesting function some ISPs have begun to adopt is called content fingerprinting.

In a nutshell, this function can scan text and even an image to make connections between senders. This is what the sender doesn’t see. Images and links within the email may contain malware and the source is scanned and the content fingerprinting takes place. This fingerprinting plays a large role in identifying specific spammers even if they attempt to hop to new IPs and domains. You would be amazed how many emails don’t land in the inbox because of links and images unbeknownst to the sender.


-Complaints– It is recommended, to try to maintain good deliverability, to keep your complaints under .03% and your combined hard/soft bounce rates under 4%. If you aren’t managing your database regularly, you will see increases in bounces. Marketers need to get in the habit of scrubbing their sending lists regularly. The age-old argument of potentially losing out on clientele is no longer valid. Marketers lose out on vastly more potential clients due to bad sender reputation and emails being flagged as spam.


-Shared v. Dedicated IP- This is a factor that tends to cause marketers to be blacklisted when they aren’t the ones sending spam. This scenario normally takes places when you have a shared IP versus a dedicated IP. A shared IP is when there is a pool of IP addresses that multiple domains are sending from. While a shared IP address is more cost effective, your chances of hitting more spam traps and blacklists increase with the amount of companies using the IP address. You essentially are all sharing the same reputation, good or bad. Being placed on a blacklist due to this isn’t always your fault but if you are sharing an IP with a company that  sends spam, it does, unfortunately, affect your sending reputation as well.

Panel data showing blacklist data


How Do I Know if I’ve Been Blacklisted?

Sometimes checking your inbox placement and noticing very low results is a good indicator that you may be on a blacklist. There are various resources to utilize to check if your sending IP address or domain has been placed on a blacklist.

  • Barracuda Reputation Block ListThe BRBL is open to the public for anyone to use, but within reason. You can register on this by providing the list of all IP addresses of your DNS that will be sending emails.
  • Spamhaus–  The Spamhaus project is one of the most reputable and trusted blacklisting companies used worldwide. It is also one of the blacklists that you do NOT want to find yourself listed on. Spamhaus can identify up to 80-90% of unsolicited messages.
  • MXToolBoxMxToolBox is a free tool to use that has multiple offerings such as MX records, DNS, blacklist, and SMTP diagnostics.
  • InvaluementInvaluement has a list of both domain names and a few IPs that are discovered within hyperlinks in the body of spam email.
  • SURBLSURBL works alongside with Spamhaus and is considered a second stage filter. It is a list of websites that have appeared in unsolicited messages- not an actual list of message senders.
  • SORBS (Spam and Open-Relay Blocking System)SORBS is known to be one of the most trusted blacklists for B2B senders. SORBS is owned by Proofpoint who also acquired CloudMark. Hotmail uses SORBS as a datapoint and it is said that Gmail may use SORBS as well.
  • SpamCopSpamCop is another blacklist that you don’t want to find yourself on. If you are sending email to an ISP that uses SpamCop from a computer whose IP is on their blocklist, your mail will be blocked and not delivered. If you can show that you can follow best practices, you can usually be delisted by SpamCop automatically after 24 hours.


How Do I Get Off of a Blacklist?

It’s important to note that most popular blacklists have a benchmark they use before blacklisting a server, and they will usually release servers from the list after a certain amount of time. Not all blacklists offer a removal center so it’s essential you do everything you can to not end up on one. In the event that you are able to be removed, sometimes you can pay to have yourself delisted. We do see, however, that some companies are delisted after paying a fee and spending some time on the list (kind of like email jail), and sooner rather than later, they end up back on the list again.This is because they continued to demonstrate the same sending practices they did that placed them on the list to begin with. Once you appear on a blacklist it gets harder every time to get yourself removed.


“Being placed on a blacklist is merely a symptom of a larger issue.”


Look within the issue which is causing the problem resulting in the blacklisting.  Keep a clean list while updating hygiene continuously, stay on top of your bounces and complaints, and evaluate what you are sending out and determine if you are following email best practices. Attempt to reconnect with users in other ways that don’t involve them marking you as spam using re-engagement campaigns.

If you have been blacklisted or think you have been blacklisted and need assistance with inbox placement, contact us today! You can also subscribe to our monthly newsletter for the latest updates and tools and trends on email deliverability.

Related Articles: How IP Warming Will Increase Email Delivery, Dedicated vs. Shared IP: How They Affect Email Deliverability, Blacklists You Really Don’t Want to be On as an Enterprise Email Marketer

Sign Up For Our Newsletter