In this guide I’m going to explain why it’s common for mail servers to get blacklisted, and what you can do if your own server has been blacklisted. For instance you can request a delisting from a blacklist.
What is a blacklist?
Depending on who you ask, most people who attempt to track the global level of spam being sent, estimate anywhere between 80%-95% of all email transmitted daily on the Internet is spam.
That means that simply relying on manually going through all of your own email, is not the most efficient method for weeding through spam messages anymore these days.
As such there are public blacklists of mail servers that have been relaying spam. This allows other mail servers to check if an email is from a server’s IP address that might have possibly been flagged for sending spam in the past.
For instance you can use our blacklist check tool to check if your server is currently listed on any public blacklists.
Why is my server on a blacklist
It’s not uncommon for a mail IP address to end up on a public blacklist, especially on a shared server. It could be due to overall volume of mail coming from that server, or messages seem to have characteristics of spam in them.
Another common cause is email forwarders. If you have email@example.com forwarding to firstname.lastname@example.org, if email@example.com is spammed, our mail server could forward that onto Yahoo.
Their servers might see our mail IP address as relaying the spam message to their server, even though it wasn’t the originating server of the spam.
Working around blacklisting problems
We monitor email queues for signs of delivery issues with major email providers. If you’re having an issue emailing a certain provider and you need to get a message sent out urgently I would recommend following the steps in my guide on sending mail via Gmail when server IP is blocked to still get your message out in a timely manner.
After that, typically you’d want to request to have the mail server’s IP address de-listed from any blacklists that it’s currently on. In order to do this you can read my guide on requesting a delisting from a blacklist.