A blacklist is a way of blocking IP addresses or domains of email servers sending out identified spam. Once a spam source has been identified, the blacklist owner will place the domain and/or IP address onto a list so that anyone can query it and block these spam sources, whether you’re an email provider like Gmail or someone running your own business.
There are literally hundreds of public blacklists in operation around the world, and even more private ones. The most widely used IP based blacklist is the Spamhaus Block List, or the SBL. Other commonly used blacklists include SpamCop and Sender Score (run by my employer).
Why Did I Get Blacklisted?
Blacklists may determine what domain or IP address to list in a variety of ways. Here are some reasons email servers are listed:
- Compromised server which is now sending spam
- Sending to suppression lists
- Sending to spam traps
- Negative user feedback
- Improperly set up email infrastructure
For example, the Spamhaus PBL list (which Spamhaus says technically isn’t a blacklist) only lists dynamically assigned IP addresses that shouldn’t be sending email, like residential ISP accounts. This approach is aimed to catch bot networks that use malware to take over consumers’ computers and use them to send spam. The Unsubscribe Blacklist (UBL) sees who’s sending to suppression files.
The majority of blacklists, however, determine listings by who is mailing to spam traps, which are decoy email addresses that were either recycled from abandoned email addresses or email addresses that have never signed up for anything.
Return Path research shows that most blacklistings occur around Christmas time. Based on my own experience, a lot of retailers and other businesses will be more aggressive in contacting subscribers around that time of year.
I’m aware of instances in which one major retailer sent to their entire bounced email file, and another emailed their suppression file. Doing so, they unwittingly sent promotional emails to addresses that had been converted into spam traps. As a result, they were listed on Spamhaus after.
I’m Listed On A Blacklist. So What?
Not all blacklists are created equal, so it’s fair for marketers to question whether or not they should care.
In the case of the blacklists listed above, marketers should care deeply — and if they are listed on Spamhaus, they should drop everything and deal with it. Being listed on Spamhaus can cause a deliverability dip of nearly 60% at Gmail.
Since Spamhaus is used by Yahoo!, Hotmail and AOL as well, your inbox placement rates can decline as much, if not more, at these domains as well.
To make matters worse, a blacklisting can last for up to 6 days for 68% of businesses. Can you imagine not being able to reach your customers for nearly a week during the Christmas season?
For most businesses this means, thousands, if not millions, in lost revenue. Add to that all the time and hours spent investigating why you were blacklisted, implementing the steps to correct it, then trying to get de-listed, and you have a pretty expensive mistake that could have entirely been prevented.
Even if you don’t see a change in your deliverability after being blacklisted, it’s a sign that you have list quality issues and that action may be needed now before it becomes a bigger problem later on.
How Do I Get Removed From A Blacklist?
- Use a blacklist monitoring service like Sender Score (again, run by my company), MXToolbox, Debouncer or another to automatically alert you when you’ve been listed.
- Check your bounce logs for the exact reason your emails are being blocked. For example, Yahoo! Mail will return this bounce code if you are listed on the Spamhaus SBL:
- 553 5.7.1 [BL22] Connections not accepted from IP addresses on Spamhaus SBL
- Request removal. Most times, the bounce log will supply de-listing information, or you can go directly to their site. Here are some of the forms for the most common blacklists:
For Spamcop, delisting may require filling out a form or just waiting a few hours for the listing to fall off. Spamhaus, on the other hand, will require working with someone on their end to develop a plan of action to correct the issue before they remove it.
Assume it’s something you did, too — taking a defensive position will guarantee that your time on the blacklist will be extended, sometimes permanently.
Now Make Sure It Never Happens Again
Part of your de-listing plan will be identifying why you got listed. Sending to a suppression file is an easy fix as long as you identify a process to prevent it from happening again. It gets more difficult when it’s a matter of list hygiene and acquisition practices where it may be necessary to re-confirm or re-permission your entire database.
Here are some tactics to ensure you’ll never get listed in the first place:
- Double opt-in or confirmed opt-in may be heavy handed, but it’s a surefire way to ensure you never get spam traps on your list. Alternatively, one can require the user check a box or some other action to be subscribed.
- Employ a win-back or re-activation program. Identify lapsed subscribers and remove them from your list before they can become a problem.
- Never buy an email list. Ever.
- Use dedicated IP addresses when sending email whenever possible, and if you have enough sending volume to warrant it.
With Christmas just around the corner, the time is now to act. To learn more about blacklists and their effect on email marketers, check out Return Path’s blacklist infographic on the topic.
Opinions expressed in the article are those of the guest author and not necessarily Marketing Land.