We’ve said it once, and we’ll probably say it 100 times more: email deliverability is the elephant in the room for email marketing.
Blocklists play a significant role in deliverability. And as far as blocklists are concerned, email content isn’t the only factor determining if a domain is blocklisted.
In this post, we’ll go over what a blocklist is, how domains end up on blocklists, how to delist a domain name, and some best practices to avoid landing on the blocklist.
What is a blocklist?
A blocklist is a collection of IP addresses, email addresses, or domains that have been flagged as sources of spam messages or harmful content. Email clients, email service providers (ESPs), and email servers usually block messages from domains or addresses on IP blocklists. Internet service providers (ISPs) sometimes prevent users from accessing blocklisted websites.
Some popular blocklists include:
Spamhaus
MXToolBox
Barracuda Reputation Block List (BRBL)
Spamcop
URIBL
Google Transparency Report
PhishTank
Email blocklists may also be referred to as blacklists. However, most of the email industry has moved away from using this term to avoid unintentional negative connotations.
How do domains end up on blocklists?
The goal of a blocklist is to protect users against spammy, malicious, or harmful content. Here are some common reasons why a domain might land on the blocklist:
The domain is sending out spammy content.
The domain’s subscribers have submitted spam complaints by marking the domain’s emails as spam.
The domain is suddenly sending out a massive amount of emails.
Emails sent from the domain have a high bounce rate.
Users aren’t engaging with emails sent from the domain.
Keep in mind that blocklists can flag domains and email addresses with good intentions. Plenty of domains land on blocklists, even if they’re steps to avoid them. Luckily, blocklisting is usually temporary.
How do I know if my domain is on an email blocklist?
Running a domain blocklist check on your email or domain helps find whether your domain (or other domains in your message) is on a blocklist. You can run your domains manually through individual blocklists or save some time by using a tool that checks your email against multiple blocklists at once.
In Email on Acid’s Campaign Precheck, you can use a domain blocklist check against four major blocklist services: Spamhaus, Phishtank, Google Transparency Report, and URIBL. We’ll let you know if your domains are on any blocklists.
