What does it mean for my local IP to be blacklisted?

Recently, we were discussing in another article about the blacklisting of Outlook, Hotmail, Yahoo, Gmail, and other email services.

But let’s refresh a bit: being blacklisted in email is like trying to go to a party and being told at the door, ‘You’re not on the list to enter.’ It’s a playful example.

Now, a question you might ask yourself is, ‘Is there a way to get into the party without being on the list?’ Or, ‘How do I know if my local IP is blacklisted?’ And, ‘What does it mean or what are the implications, in less technical terms?’

If your IP is blacklisted, unfortunately, you can’t get into the party… But there’s a distinction we need to make: perhaps on the guest list, you’re registered under a different name…

We need to differentiate between 2 types of IPs: one is the server’s IP, and the other is the local IP. The one your internet provider gives you at home or in the office is the local IP, and the server’s IP is the one assigned with the email service. The difference is that the local IP changes; it’s not a fixed or dedicated IP, whereas the server’s IP is a dedicated one.

There’s another differentiation not commonly known because it’s technical, but when you send an email through a webmail, meaning from the web browser, you’re forcing the email to take the server’s IP to send it. In that case, you’re not using the local IP.

However, if you use Outlook, for example, you’re forcing the system to use the local IP to send the email; Outlook doesn’t take the server’s IP. When you send an email to a client and they don’t receive it, the first thing that comes to mind is, ‘My email provider is having issues.’ The more experienced among us check if the server’s IP is on public blacklists, and not finding it, think, ‘Yes, definitely my email provider is having problems.’

Let’s debunk the myth.

In these cases, I recommend going to https://cualesmiip.com. This page indicates your local IP; copy it, then go to MXtoolbox.com (the link already has the blacklist section location).

Paste your local IP, and it will search if it appears on any blacklist.

If you’re a more experienced user, you can go to CMD on your computer if you have Windows and type the command: ‘ipconfig’ without the quotes. It will return your computer’s local IP.

If you do appear on the blacklist, your emails sent via Outlook will be blocked. The next step to check this theory is for you to go to your webmail and try to send an email from there, without using Outlook, but forcing the email to go out with the server’s IP. If the email gets delivered, then we have a culprit… The local IP.

Now, you might wonder, But if I haven’t sent mass emails, why am I blacklisted?’ ‘Why is my local IP blacklisted?

It could be that your internet provider gave you an IP that was already on blacklists; it’s not mandatory that it was because of emails you sent. While it’s indisputable that IP blocking is for sending SPAM, this is a case where it may not necessarily have been sent by you; when you received the IP, it might have already had the ‘flu.’

It’s clearer now, but what about now: How do I get my IP off the blacklist?

In Mxtoolbox, there’s a list where your IP is blocked and it indicates which server is blocking it; you go to that page and fill out the form they ask for, indicating the reasons why they should remove you from the list.

Another way is for you to turn off your internet router for about 5 minutes and when you turn it back on, it’s very likely that your internet provider will assign you a different IP. At this moment, you validate again on cualesmiip.com that it has indeed changed by comparing it with the IP the same page had generated before. And then on the MXtoolbox link, you validate that this IP is not on public blacklists now.

Can it happen that my new IP is blacklisted again?

Yes, it can happen; the probability that the next IP is blacklisted starts to decrease, but it could still be blacklisted again. In these cases, you can try restarting the router again or contacting your internet provider for support. It could also be that a device on the network has a virus and is sending mass emails without you knowing. You can refer to this article that explains this case: https://netquatro.com/contact-us

I can’t turn off the router in my office because it’s very important for the internet to always work.

In this case, you can contact the providers who have your IP blacklisted to delist you or you can contact your internet provider for support.

However, if you can’t find a way to fix this issue, you can write to support, and we’ll gladly help you resolve this case.

We open the comments, have you ever been blacklisted? How has it affected you and how did you solve it?