Email Deliverability: Part 4 – IP Address Reputation

What is a “blacklisted IP”?

Unfortunately, one of the issues that web hosting providers have to deal with is IPs that are blacklisted. These often are caused by previous users of that IP, one of their own customers sending spam, or some other reason. The first step you’ll want to perform is to utilize a few different websites that enable you to check the reputation of a specific IP address you are provided. Some of the tools that are frequently used (and we are not affiliated with) and we suggest trying to use are:

Access any of the above websites, enter the IP address that you have received for your web hosting account, and let them check each of the lists. Now, each of those sites roughly checks the exact same list of black list databases, but it can’t hurt to have multiple sources verifying the information.

NOTE: If you have entered your domain’s IP in any/all 3 of the services linked above, and they all are showing that the IP is not blocked, you may stop reading this article; there is nothing more for you to do.

How do I get an IP removed from a blacklist?

This is a VERY tricky part of this process and the part you’ll likely spend the most time working on. Each blacklist has its own criteria for flagging IP addresses and compiling a list of offenders. Those criteria may include various measures, some technical, policy-based, and some evidence-based.

Technical listings occur mostly from misconfiguration of a mail server, such as incorrect or missing DNS records, missing or incorrect banner greetings, and even mail servers operating in a suspicious IP range.

Policy listings are based on an operator that does not wish to receive email from certain countries or ISPs that have a history of not respecting any “Unsubscribe” headers that are included in emails.

Evidence-based listings are those where an operator has received direct evidence that an IP address has been involved in sending spam emails.

If you find that one of the services that you used has returned your IP as a blacklisted address, then you’ll need to go to each of those websites and perform an IP lookup on their site, using their interface. Most of the blacklist websites will provide a general listing error, but won’t give specific details about why or what was the cause of the listing.

Getting Your IP Removed From Blacklists

If you are able to find out the reason for being blacklisted, great! Now work to reverse the cause of the blacklisting, further helping your domain and IP reputation. If you were not able to find out the exact reason, then you need to start looking at other options.

If you are not aware of why your IP is blacklisted, then go through each step for verifying your SPF, DKIM, and DMARC DNS TXT entries are correct. Once you have confirmed that these are all valid, using the tools from each of the previous articles in this series, then you’ll need to go through the process for each blacklisting service to have the IP removed. Sometimes this is a simple form describing why it should be removed. Sometimes it’s going to be a more rigorous process to have the IP removed.

If you aren’t getting anywhere with following the blacklist removal process, then it may be worth calling the blacklisting service directly and asking to have it removed. This may net you better results, but be prepared for these services to outright refuse to remove your IP.

Unfortunately, sometimes removing an IP isn’t something that a person can do, and instead is based on how much time has passed. In this case, the blacklisting service usually has a time-based removal process based on how severe the offense was.



Whew! You made it to the end of this series! Congratulations! Hopefully, this has been helpful and you are seeing significantly better receipt rates for your emails. Just remember, if you change web hosting providers, or change your DNS provider (like switching to Cloudflare or others), then you’ll have to ensure that your DNS entries match that provider and the web hosting provider service.

If you are still needing assistance with your email reputation, please feel free to reach out to us via a support ticket or by emailing us. ([email protected])

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