You are clear, buddy!
Crafting a compelling email takes time, creativity, and energy, which is why it can be so frustrating to see the email never reach its intended destination. Some emails never make it to the inbox because they’ve been sent to the wrong email address, are too large, or contain suspicious attachments. All these problems can be easily fixed.
However, what if an email is rejected because the sender is blacklisted? In that case, the solution is more complicated and not well-understood by most email users.
What Is an Email Blacklist?
An email blacklist is a list of IP addresses and/or domain names that are known to send spam emails. Such lists are compiled by independent blacklist operators, organizations, and internet service providers (ISPs) to help them combat spam.
Some of the largest and most prominent email blacklists include:
- Spamhaus Block List (SBL): This email blacklist is a database of IP addresses from which Spamhaus does not recommend the acceptance of email messages. It’s queriable in real-time by email systems through the internet and maintained by a dedicated team of investigators and forensic specialists located in 10 countries.
- Composite Blocking List (CBL): A subdivision of Spamhaus, CBL only lists IPs exhibiting characteristics that are specific to open proxies of various sorts and dedicated spam bots known to send spam emails.
- Spamhaus Exploits Black List (XBL): XBL is yet another Spamhaus email blacklist that deserves to be mentioned. It includes IP addresses of hijacked PCs infected by illegal 3rd party exploits, incorporating data from several other lists of spam sources to be as comprehensive as possible.
- SenderScore: This email blacklist aims to be sort of like a credit score for email messages. It rates senders from 0 to 100 based on their reputation, taking into consideration a large number of metrics, including spam complaints, mailing to unknown users, industry blacklists, and more.
- URIBL: Unlike the previous four email blacklists, URIBL is a domain-based email blacklist that lists domains that appear in spam. Email and internet services providers can incorporate this blacklist to catch emails containing malicious URLs.
- Barracuda Reputation Block List (BRBL): Launched in 2008, BRBL is a free and open list of IP addresses known to send spam. Anyone can use this list free of charge after completing a simple registration process.
- LashBack (Unsubscribe Blacklist): This unique real-time blacklist of IP addresses which have sent email to addresses harvested from suppression files contains approximately one million entries.
Major email providers, such as Google and Microsoft, maintain their own private email blacklists, which may or may not incorporate data from the above-listed public email blacklists.
To check if an IP address or domain name is blacklisted, it’s best to use an email blacklist checker capable of analyzing many different email blacklists in real-time, such as EmailListVerify. Simply enter the IP address or domain name you want to check and wait for EmailListVerify to display the results.
How Do Email Blacklists Work?
All email blacklists work the same way. A receiver receives an email from a sender. The sender’s IP address is checked against a blacklist. If the IP address isn’t present on the blacklist, the email message is accepted. If the IP address is present on the blacklist, the email message is rejected, and it may also be tagged for future reference.
But how does an IP address or domain name end up on an email blacklist in the first place? There are several possibilities:
- High volume of sent emails: According to the latest global spam statistics, spam accounts for around 45% of all sent emails, which means that spammers are among the most active senders in the world. A very high volume of sent emails is a strong sign that the associated IP address or domain could be a source of spam.
- Surge in email sending: It’s very rare for legitimate senders to suddenly send out hundreds or thousands of email messages. Spammers, on the other hand, know that time is against them, so they do what they can to target as many email addresses as possible in the shortest amount of time possible.
- Suspicious content: Spam emails typically contain links to malicious websites, include malware disguised as innocent attachments, and use common spam triggers words and phrases.
- Spam complaints: Email recipients have the option to mark an email as spam if they don’t trust it. High spam complaint rates are a surefire way how to end up on an email spam list because both email services and ISPs take them very seriously.
- Bounced emails: Legitimate email lists don’t contain many dead addresses, but that’s not the case with email lists used by spammers, which often come from the dark web and contain thousands and thousands of scrapped email addresses, many of which are either dead or spam traps, honeypots used to collect spam to identify spammers and block emails from them.
How to Remove IP/Domain from an Email Blacklist?
Ending up on an email blacklist isn’t such a big deal as it may seem at first. The truth is that there are possibly hundreds of email blacklists, so the chance of you being included in at least one of them is very high. Most email blacklists are fairly inconsequential because no major ISPs or email services use them.
If you end up on one of the major blacklists, such as those listed above, you need to familiarize yourself with their unlisting process and send a removal request. The owner of the blacklist may require you to take a certain action, and it’s very likely that your activity will remain monitored for some time.
Not all blacklists have a formal unlisting process, however. To remove your IP address or domain from an email blacklist that doesn’t provide any official removal procedure, your best bet is to contact the owner of the blacklist via email and explain the situation.
Reducing Your Risk of Getting on an Email Blacklist
To reduce your risk of getting on an email blacklist, it’s critical to always monitor all important email engagement metrics, such as open rate, bounce rate, and the number of unsubscribes. By sending emails that actually perform well and are well-received by their recipients, you dramatically reduce the chance of getting on an email blacklist, and, at the same time, accomplish your objectives.
Make sure to build your email list legitimate, with email opt-ins. Never buy an email list because sending emails without an opt-in is a textbook definition of spam. What’s more, many emails on any purchased email list are guaranteed to be either dead or spam traps.
It’s also highly advisable to avoid sending too many emails at once. Marketers can take advantage of many email marketing tools that allow them to schedule emails and send them out gradually over a certain period of time. The same tools can also automate email opt-ins and email opt-outs, which all legitimate emails should always include.
Finally, never send emails with attachments of any kind in bulk unless you’ve already established a good relationship with all recipients. Many spam filters are configured to instantly mark all emails with attachments as suspicious, and that includes emails with direct links to files.