How to Restore the Ability to Send Email When your SPAM Filter Company Gets Blacklisted

Many companies use an external vendor to filter through all incoming and outgoing emails looking for SPAM. There are several companies that provide this service and the purpose is to help prevent SPAM emails from being delivered to users on your network, in addition to preventing SPAM emails from being sent out from your domain.

This post shows what you can do if you use a SPAM filter and that company is blacklisted which in turn, blacklists any company relaying their email through them.

How to Restore the Ability to Send Email When your SPAM Filter Company Gets Blacklisted

Using a SPAM filter is a good idea because it helps protect your domain from sending and receiving SPAM emails. The reason preventing SPAM from being sent or received is so important is that if your domain ( is detected as being a sender of SPAM, you can be blacklisted. If your domain is blacklisted, SPAM filters will not allow email from or to you to be delivered which can have a huge negative impact on your staff's ability to be effective.

To understand how to fix this issue, it is important to be aware of how an external SPAM filter works. Once you have selected a provider who will filter your email for SPAM, you must set up all of your email to relay to that SPAM filter. This is done using by modifying mail exchange (MX) records wherever your DNS records are hosted.

With a SPAM provider chosen, your domain MX record needs to be updated to tell your email provider that you want your outgoing email sent to and incoming email received by the SPAM provider. This is how the SPAM provider becomes a relay for your email. The SPAM provider scores each to determine if there are enough items to flag the email as SPAM, or allow it to pass through.

As the recipient of outgoing email, the SPAM provider checks user email to be sure they are not intentionally or inadvertently sending email that will be considered SPAM on the receiving end. Additionally, the SPAM provider checks incoming email before passing it along to the intended recipient, or blocking it from getting to that person if it is determined to be SPAM.

Most of the time, any emails blocked from being passed on can later be passed on by the administrator of the SPAM filter where the email was incorrectly identified as SPAM. Additionally, emails that did pass the filter can often be blocked in this same interface if it is in fact determined to be SPAM by a user or the administrator.

Unfortunately, if the SPAM provider you have chosen is themselves determined to be a SPAM risk, as happened last week with SonicWall, all of their customers were also considered SPAM because SonicWall was their relay. If this ever happens to you, there is a quick way you can get your outgoing and incoming email working again until the SPAM filter is back up and running.

To get email working again, you simply need to cut out the relay to the SPAM filter provider. To do this, log into your DNS hosting provider and update/remove the MX records.

Example of an MX record relaying email to SonicWall.

Some things to consider before making changes:

  1. If you are using Microsoft Exchange for your email, you can add an MX record to relay to which will relay your email through Microsoft.
  2. If you are not using Microsoft, your best option is to remove the relay record and have email send directly to and from your email provider - in essence bypassing the SPAM filter.

If you fall into category one above and have Microsoft as your email provider, you can simply add an MX record to include their relay information and set the priority to a number lower than the number associated with the SPAM provider. This works because MX records are processed from lowest to highest number. Creating an MX record with a lower number than the SPAM filter provider allows email to be relayed to Microsoft instead so you can get email again. Be sure to check the SPAM provider and update the priority numbers when it is appropriate.

If you fall into Category two above, you will simply want to remove the MX record relaying email to the SPAM provider. Before you do this, be sure to take a screenshot or document the record in some way where you will have access to it later. Once the SPAM provider is back up and running you can update the MX record to relay to their service again so emails will be processed as they originally were.

While the odds of a SPAM provider being blacklisted are low, it can happen. If it does, you simply need to update your mail exchange record so that email relays somewhere else, or comes directly. Be sure to check back with the SPAM provider and set the records back to them as your relay once they are back up and running as you want to reduce your SPAM risk as much as possible.

As always, knowing how to quickly work around issues that arise is key in being responsive!