Email Blacklists - Are your emails getting bounced?

2 Aug 2013 1:41 PM Email Blacklists - Are your emails getting bounced?

When you send an email to certain recipients (but not necessarily all) are they coming back as rejected? If so, one of the causes may be your IP address, a unique number sequence that identifies each computer attached to the Internet, is in one of the blacklist databases the recipient’s mail server checks.

What is a Blacklist?

It is a database of IP addresses that are listed as spammers. The mail server receiving the email address may check one or more of these databases for the IP address of the sender and if listed will bounce the email back to the sender. The Inology mail servers, for example, check 3 of the most reliable blacklist databases for the sender’s IP before delivering the email to the recipient’s mail box.

Checking Blacklists

It is hard to tell what blacklist databases the recipient is using however, it may tell you in the bounced return email if you got one but unfortunately that is not always the case. You can however check the popular lists to see if your IP address is on any of them.

First you need to determine what your IP address is. That’s easy, go to Google and type in “what’s my IP”. Copy the IP address and go to or for a more comprehensive search go to and input your IP address.

Blacklist Results

If they all come back clear then it is unlikely it is blacklisted and the cause of your email not getting through, unless the recipient is using a blacklist that was not checked. Even if you get 1 or 2 hits still does not mean that is the cause for this particular recipient. However, it is a good place to start.

Scan your Computer(s)

If you have found your IP address on any of these blacklists you should have your computer(s) scanned for vulnerabilities such as viruses, trojan spam-senders and other security compromises. Ask your IT guru for the best method of scanning and cleaning your computer of these vulnerabilities if any.

Solution for Dynamic IP Addresses

If your IP address is on one of these blacklists it doesn't necessarily mean your computer is sending spam. Your Internet Service Provider (ISP), the company you use to connect to the Internet, will more than likely assign you a dynamic IP address each time you connect to the Internet. This IP address may have been assigned previously to a computer that was spamming and caused it to be blacklisted.

Note: even if you think it was a previous computer with the problem you should have your computer scanned for vulnerabilities before proceeding.

Once scanned and all clear simply turn of your modem for 10 minutes and restart. This should force the assignment of a different IP address which may not have been blacklisted.

Solutions for Static IP Addresses

If you have a static IP address, meaning it is the same every time you connect to the internet, you will need to get your IP de-listed from the database(s).

With some databases your IP may automatically drop off the blacklist after a specific time period which could be hours, days or even weeks. While others you can submit your IP address for removal. Be wary of those that request payment for removal. Most mail servers do not use these databases and it is unlikely the recipients mail server is.

Note: before you attempt de-listing you should have your computer scanned for vulnerabilities.

The site you used to check the blacklist may give you a link to the database where you can request removal from, otherwise search for it with Google, for example: “removal from”.

Are emails sent to you getting bounced?

Is someone trying to send you an email and has let you know they are not getting through due to blacklisting? If so, give them this article.

Further Assistance

I hope this was helpful. If you require further assistance please contact Inology and we will do our best to help you.