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SMTP Connect

What you see when your domain has this problem
Unable to Connect to SMTP Host Details area Ignore
Add blacklist monitor for 162.247.75.111

More Information About Smtp Connect

We attempted a connection to your mail server on port 25 but your server did not respond. More than likely there is no email server at this address or you have a misconfigured firewall or spam filtering system.

If the SMTP Connect test is unable to connect to your mail server after 15 seconds we will report it as an error. For optimal email deliverability it is advisable that SMTP connections should not take longer than 15 seconds.

Firewall Information

Here are the networks MxToolbox uses for SMTP Tests. Please add these to your firewall to avoid experiencing connection failures or false alerts.

  • 64.20.227.128/28 (Netmask: 255.255.255.240)
  • 208.123.79.32/27 (Netmask: 255.255.255.224)
  • 54.84.234.24, 54.164.124.219, & 54.88.4.135

Additional Information

Tarpitting

It is also possible your server is “Tar pitting.” Tar pitting is a technique used by some email servers to slow down spammers. The idea is that legitimate senders will wait longer to establish a connection than spammers will.

Here is a link to a link to the TechNet article with more information about Tarpitting

Back Pressure

Our SMTP test cannot detect problems caused by Back Pressure, a system resource monitoring feature of the Microsoft Exchange Transport service. In order to be alerted for back pressure events you would need to add our end-to-end Mailflow Monitor for your server which can detect any type of email interruption and also provide historical performance data.

Here's a link to the TechNet article with more information about back pressure.

Your Email Deliverability is in Jeopardy!

Blacklisting is a sign that you are not actively managing your email deliverability. Other technologies - SPF, DKIM and DMARC are now just as important to get your email placed in the Inbox of your recipients. If you aren’t managing email deliverability, your message may never be heard.

MxToolbox Delivery Center Features:

  • Insight into your SPF, DKIM and DMARC configuration to ensure your sending email properly
  • DMARC Compliance checks for all of your reported email
  • Adaptive Blacklist Monitoring of all your email senders
  • Recommendations for improving DMARC compliance and DMARC policies
  • Event-based reminders for emergent issues and on-going maintenance

DMARC is a necessity for your business!

  Learn More about Email Delivery

burritos@banana-pancakes.com braunstrowman@banana-pancakes.com finnbalor@banana-pancakes.com ricflair@banana-pancakes.com randysavage@banana-pancakes.com