As an email marketer, you’re probably familiar with blocklists already such as the Composite Blocking List (CBL blocklist). You can think of a blocklist as a sort of gatekeeper that only lets certain emails reach their destinations while stopping others.
One aspect of a blocklist is to protect email users from receiving unsolicited emails that could potentially contain malicious content. This is especially true with hackers employing shady tactics to introduce a Trojan horse or stealth spamware to computers.
According to research, 45% of global data breaches incorporated hacking techniques with the majority of these breaches carried out by external actors.
Yet no matter how careful you are at toeing the line, legitimate email senders could still find their IP addresses listed in these blocklists. An IP address that has been added to one of these lists will have a harder time completing direct mail transmission of the user’s messages to their subscribers.
If you somehow find yourself added to the Composite Blocking List, then you need to work on CBL delisting as soon as possible. But first, let’s understand what CBL is and how it works.
What Is CBL?
As mentioned above, CBL stands for Composite Blocking List, which uses different SMTP server installations to create its own database containing blocked IP addresses.
CBL does not list every IP address that produces spam. Instead, it only lists those exhibiting characteristics of using various types of open proxy, spam bots, viruses, and malware. If your mail server is using botnets, it also keeps track of those.
A couple of situations where you won’t be listed by the blocklist are:
- Your IP address is shared or have a higher probability of being shared with legitimate senders
- Your IP address is from one of the many open SMTP relays
These SMTP open relays are those mail servers that have been misconfigured to accept any message from the web. It also allows sending emails to anyone online.
A mail server must be configured to disallow incoming email that’s not meant for their users in their database.
How Can I Remove My IP From the CBL?
The lists maintained by blocklists like CBL will expire automatically after some time. However, you can help speed up this process so you can get back to sending your legitimate emails right away.
Begin by performing an IP look at this CBL lookup URL. If you find your IP address listed on the blocklist, you can expect to be given further details on how you can start the CBD delisting process. Keep in mind that having your IP delisted is free and will not cost you anything.
Simply follow the instructions provided to have your IP address removed from their block list. Another thing to note is that you’re expected to fix the problem that led to your listing.
You should get this done before going through with a delisting. This is because if you get flagged again for potential spam activity, you will be listed once again and the consequences for that will be more severe.
Main Reasons to Get Blocklisted
The CBL blocklist will add an IP address to its list if one or more of the following conditions are met:
- The sending IP address has indications that it is infected with a spam-sending worm or virus
- The IP address has been flagged for using botnets
- The IP address is using open proxies to send spam emails to other users
Open proxies are non-mail servers that have been converted into machines that will send out messages to third parties. Usually, malicious individuals use these web servers, computers, or web proxies that contain spamware that have been infiltrated by a Trojan downloader.
Whether an IP is dynamic or not, the CBL will blocklist it once it has confirmed that it has been infected. Furthermore, it will not provide you with supporting data as to why your IP address has been listed.
How To Avoid Getting Listed
Now that you know how strict the CBL blocklist can be, you must keep your nose clean so you can avoid being listed. Delisting can take some time to process so it’s important for you to stay away from it as much as possible.
The main consequence of being added to the blocklist is that your email sender reputation and deliverability will suffer. This means that you will find it more difficult for your emails to reach their intended inboxes – if you’re even allowed to send.
Make sure that you perform a full security check on your mail server to ensure that there are no viruses, open proxies, or Trojan horses that are sending out spam. You should also see if there are any unusual misconfigurations with your email setup.
Even the slightest of problems can land your IP address in the CBL, not to mention the other block lists out there.
To Wrap Things Up
The CBL blocklist is one of those block lists that email senders should avoid at all costs. Not only can it hamper your ability to send emails, but it could also cause your sending reputation to suffer.
In case you find yourself listed here, there is still hope for you to get delisted. CBL delisting is easy so long as you follow the proper procedures that will be provided to you.
You should also ensure that any potential mistakes or misconfigurations on your end have been fixed to increase your chances of being removed from the blocklist.
