Email Blacklist

May 5, 2024

An email blacklist, also known as a DNS-based Blackhole List (DNSBL) or Real-time Blackhole List (RBL), is a database or list of email servers or domains that have been identified as sources of spam or other malicious activity. Email blacklists are used by email servers and spam filters to block or flag incoming emails from blacklisted sources, preventing them from reaching users’ inboxes.

Here’s how email blacklists work and their key characteristics:

Listing Criteria:

Email blacklists maintain criteria for identifying spam or abusive behavior. This may include factors such as the volume of email sent, the presence of spam traps, complaints from recipients, or other indicators of spamming activity.

Dynamic Updates:

Email blacklists are frequently updated to reflect changes in email server behavior and emerging threats. New sources of spam are added to the blacklist, while delisting procedures may exist for legitimate senders who have resolved their issues and complied with listing criteria.

Public Access:

Many email blacklists are publicly accessible and can be queried by mail servers or spam filters during the email delivery process. Mail servers check the sending IP address or domain against one or more blacklists and take action based on the results, such as rejecting or flagging emails from blacklisted sources.

Impact on Deliverability:

Being listed on an email blacklist can have a significant impact on email deliverability. Emails sent from blacklisted servers or domains may be blocked, rejected, or marked as spam by recipient mail servers or spam filters, resulting in undelivered or discarded messages.

Whitelisting Procedures:

Some email blacklists provide procedures for legitimate senders to request delisting or removal from the blacklist. This typically involves submitting a delisting request and demonstrating that the issues that led to blacklisting have been resolved, such as addressing spam complaints or securing email servers.

Different Blacklists:

There are many different email blacklists maintained by various organizations and security companies. Each blacklist may have its own listing criteria, update frequency, and impact on email deliverability. It’s essential for mail server administrators and email senders to monitor and address listings on multiple blacklists if necessary.

False Positives:

While email blacklists are effective at blocking spam, they can sometimes result in false positives, where legitimate emails are incorrectly flagged or blocked. It’s essential for email senders to monitor their email deliverability and address any deliverability issues caused by blacklisting.

    How to find out if your is email blacklisted

    It can be tough to know for sure if you’ve been blacklisted. If you want to know the answer to “Is my email blacklisted?”, sometimes Google will notify you. However, the email client doesn’t always deliver a notification. If you notice a steep drop-off in responses and traffic, that might be the only sign you get.

    You can check if Google has blacklisted you by making a Google account and viewing the Security Issues Report. There, you’ll see a list of URLs that Google has been alerted to. If you find your site on the list, the first step is to clean your site of malware and let Google know you have fixed the problem.

    If you learn Google isn’t blocking you, you’ll need to go down the list of databases to check email blacklist sites for your mail server IP address or domain name. The most common email blacklist checker sites are:

    • GradeMyEmail Blacklist Checker
    • MXToolbox’s Blacklist Check
    • Barracuda IP Blacklist Checker
    • Whatismyip Email Blocklist Checker
    • DNSBL Blocklist Check
    • MultiRBL/DNSBLs Blacklist Lookup Tool
    • Spamhaus IP Blocklist Checker
    • IPVoid Blacklist Checker
    • DNSChecker IP Blocklist Checker
    • SpamCop

    If you find you’re on one of these lists, they’ll have a protocol for removal. This usually consists of getting a report of the problems or suspected issues, clearing them up, notifying the database managers, and waiting. Most of the time, you can get removed easily, except in the case of SenderScore.

    Tips to prevent your email from getting blacklisted

    Avoiding email spam filters altogether can be tricky. If hackers are attacking your site or spoofing your email, you might get on a list to no fault of your own. This happens more often than we would like, but that’s part of the reason it’s usually easy to get off a list.

    Here are a few things you can do to reduce the risk of your email being blacklisted.

    • Create high-quality, engaging content
    • Ensure your contact list is up to date
    • Avoid spam words
    • Refrain from sending mass emails via Internet service providers (ISPs)
    • Get consent before sending emails
    • Don’t purchase email lists (some purchased email lists can contain spam traps)
    • Remove email addresses with typos from your email list

    Overall, email blacklists play a crucial role in combating spam and protecting email users from unwanted or malicious messages. By blocking emails from known sources of spam, blacklists help maintain the integrity and security of email communications. However, it’s essential for organizations to maintain good email practices and address any issues that may lead to blacklisting to ensure reliable email deliverability.