Tech Tips

February 23, 2016

Consumer-Grade Email is Vulnerable to Blacklisting—Don't Use it for Business!

Does your email bounce back for no reason? If you use personal email for business purposes, your email address might have ended up on a blacklist. Here's how it happens, and how you can check.

We've fielded several support calls from small companies recently about emails bouncing back. Their emails were returned as "undeliverable" with no explanation.

What happened? The customer's email address was on a blacklist.

Email blacklists track which Servers or IP addresses have been classified as spam sources, and prevent them from sending any messages out.

But what if the customer never sent any spam out? Why would they get added to a blacklist if they didn't do anything?

Consumer-Grade Email Gets Stuck on Blacklists

In many of these cases, we found that the company was using consumer-grade email accounts, like Gmail or AT&T.

The problem with consumer-grade email accounts is that they use dynamic IP addresses. Think of an IP address as the channel through which the email goes. If the IP address is dynamic, that channel changes locations once in a while.

Blacklists keep lists of IP addresses which were used for sending spam in the past. If your email account changes to an IP address that’s marked as a "known spammer"...then your email address gets blacklisted too.

Unfortunately, it happens. It's no one’s fault, and it doesn't mean your emails are spam. It just means some high-security mail servers think they are.

How to Check If Your Email is Blacklisted

Not sure about your email address? You can check if it’s blacklisted online. Here’s how you do it.

  1. Log onto your computer.
  2. There are two possibilities for the blacklisted element – the specific email address, or the outgoing IP address. We always check both.
    • To find your IP address, type "what is my ip" into Google. Google will show you your exact IP address.
  3. Go to This website has a blacklist checker tool called MX Lookup. It’s free to use.
  4. Enter your email’s domain name (e.g., into the MX Lookup Tool box. Click the "MX Lookup" button.
  5. In the scan results, you'll see a "Blacklist Check" link on the right. Click it.
  6. A long list of known blacklists will display. If your email address IS on a blacklist, one or more of these blacklists will show a “LISTED” flag with a red button.
  7. If you see this, please contact us as soon as possible! It will disrupt your emails until fixed.
  8. Repeat these steps for the IP address too.

Because of this blacklisting risk, PlanetMagpie recommends never using consumer-grade email accounts for business email. Business email accounts typically use static IP addresses – the same channel, every time. That eliminates the possibility of a "known spammer" IP address getting in the way and bouncing your emails back.

Does your email address show up on a blacklist? Please call us at 510-344-1203 so we can help!