Email Blocklist Check

How do senders get blocklisted?

Senders’ IPs and domains are typically blocklisted for having high spam complaints and sending to spam traps. Blocklist operators don’t have an issue with legitimate senders, rather their focus is on protecting email consumers from bad practices and fraud. Usually, when a legitimate sender gets listed it’s because their campaigns have characteristics of a spammer.

Here’s a little more detail on the ways you could land on a blocklist:

• Spam complaints negatively impact your ability to land in a subscriber’s inbox. If subscribers consistently mark your email as spam, your IP may end up on a blacklist. To avoid this, ensure your email content is value-added and relevant to your subscribers.
• Sending to spam traps is a symptom of poor list acquisition and list hygiene practices. To avoid this, use opt-in consent and regularly suppress unengaged subscribers. Blacklists also use spam trap addresses — which are fake (so-called pristine traps) or inactive (recycled, unused) email addresses — to determine the quality and accuracy of your email list.
• Poor mailing lists are important to avoid. Mailing lists can become increasingly inaccurate if companies have weak permissions and/or fail to observe opt-out requests. Follow consistent list management to avoid inaccurate mailing lists.
• Sudden high volume sending can also get you blocklisted if you have little to no established sender reputation. Avoid sending campaigns all at once or in quick succession if you’re sending from a new domain or IP address.
• Misconfiguration of your email infrastructure—for example, if your reverse Domain Name System (rDNS) does not match your HELO—can also lead to being blocklisted.

Is your company blocklisted?

If your email open rates have suddenly taken a dive, it’s time to do a blocklist check. It is impossible to monitor all of the web’s email blocklists and spam trap networks. They are too numerous, and many don’t offer public data feeds. Some websites will let you manually spot check your domains and IPs for blocklisting. You can also use an email success platform such as Validity’s, which includes reputation monitoring to check if your IPs and domains are listed on important blocklists.

What does being blocklisted mean for your email campaigns?

Once your domain or IP address appears on blocklists, you’ll begin to see critical issues with your email program’s engagement data and bottom line — especially if they appear on major blocklists, such as Spamhaus. Mailbox providers use these blocklists to ensure spam doesn’t land in their users’ inboxes. To ensure that your emails are delivered, it’s essential to regularly schedule blocklist status checks.

However, there are hundreds of blocklists, and not all of them have the same impact on email programs. So rather than panicking if your IP or domain pops up on any blocklist, check if it is an important blocklist and determine if your performance metrics are impacted.

Types of public blocklists

There are two types of public blocklists your business may find itself on: IP-based blocklists and Domain-based blocklists.

IP-based blocklists are used by mailbox providers to identify which IP addresses are sending spam or other “bad” mail, such as malware infectors, virus and botnet distributors, to their receivers.

Domain-based blocklists utilize the senders’ domain names to create lists of domains associated with spam. These domains aren’t necessarily sending spam to receivers, but they were found to be using bad practices associated with spam attempts. Make sure to follow email best practices when creating email campaigns.

Not all blocklists are created equal. Some blocklists have a bigger impact on performance.

If you’re blocklisted, there are steps you can take to address mitigating factors that led to your IP or domain being blocklisted. Temporarily stop your email campaigns and figure out exactly how and why this happened. If you’re on a critical blocklist, like Spamhaus, follow their delisting process. Learn more about this process and blocklist prevention here.