A blacklist or a blocklist is a list of IP addresses that are considered to be distributing spam
A blocklist is used by ISPs(Internet Service Providers) as a filter to block messages that are believed to be malicious. It uses pieces of information and a set of criteria to determine whether an email contains spam or not.
When a blacklisted domain or IP address sends a message, it’ll be automatically sent to the spam folder. Unfortunately, non-spam emails can get on the list too. Therefore, it’s crucial for marketers to take steps so that their email marketing doesn’t end up on the list.
Some of the indications that your email is on the blacklist:
- You have a high bounce rate. This can indicate that your email has been blocked before even reaching the inbox.
- You may get a message from a blacklisting organization (such as Spamcop, Spamhaus, Barracuda) about your email being on the list.
What causes it?
Many factors determine whether an IP or domain is sending malicious messages. Here are some possibilities:
- Poor feedback from users and negative actions towards your address, such as deleted emails and spam complaints.
- You’re sending large quantities of email as this can be flagged as spam
- Including attachments (where malware is usually housed) can have a higher chance of being blacklisted.
- Having too many graphics can trigger spam filters.
How to avoid it?
- Make sure you know what your IP address is. Then, insert your IP into an online free tool(such as MxToolbox and WhatIsMyIpAddress) that can tell you if your address has been included on a blocklist.
- If that’s the case, you can send a removal request. It’ll tell you the steps on how to remove your IP or domain from the list.
- Apply best practices like displaying your contact information in your emails, including unsubscribe links, using a double-opt-in for your subscribers, and creating valuable email content.