G Suite Catchall Email Address using 33mail

If you manage your domain using G Suite you may be interested to know that you can use it in conjunction with 33mail as a catchall service. This way you get all the benefits of 33mail (easy management of aliases, managed replies, etc) while also routing your primary address through G Suite with all of its features.

Setup is simple but will require a 33mail Premium account (only $12 per year)

NOTE: This feature is only available on paid G-Suite accounts. If you have a ‘Legacy Free’ account It will allow you to set up the route but it will just bounce emails instead of forwarding them.

  • Log into your gsuite admin account and go to Gmail Settings

    • https://admin.google.com/==your gsuite domain==/AdminHome#AppDetails:service=email


    • From G Suite home : https://admin.google.com/==domain==/AdminHome
    • Click the menu at the top left
    • Select Apps -> Gsuite -> Gmail
  • Select Hosts

  • Select Add Route

    • Name : 33mail routing
    • Select Single host
    • Host name: domains.33mail.com
    • Port: 25
    • Uncheck ‘Perform MX Lookup on host’
    • Uncheck ‘Require secure transport’
  • Click save

  • Select the ‘Default Routing’ Section

  • Click ‘Add Setting’

    • Select ‘All recepients’
    • Select ‘Modify Message’
    • Check ‘Change route’
    • Select 33mail routing
    • In options
    • Select ‘Perform this action only on non recognised addresses’
    • Click save
  • Thats it.

  • Setup your domain in 33mail and G Suite will pass mail for any address not handled by G Suite will be passed to 33mail for processing.

1 thought on “G Suite Catchall Email Address using 33mail

  1. John Tangney

    This is fantastic! Thank you!

    The gmail instructions are super-detailed and while the wording has changed a little since November, absolutely spot-on.

    One step missing from your instructions: Be sure to add the domain under “Custom Domains” in the Settings page. Otherwise the email will be rejected by 33mail.

    I was also curious about whether I need to add an MX record to my DNS as instructed under “Custom Domains”. (Works fine without it.) But I guess that’s just for sub-domains? Or maybe that’s why you say to “Uncheck ‘Perform MX Lookup on host’”, right?

    Finally, the tinfoil-hat security engineer in me balked a little at turning off TLS. However, once I regained my composure, I realized that the threat is miniscule. Basically, allowing unauthenticated and unencrypted email from Gmail to 33mail is perfectly fine for my use case, namely handing out email addresses for online purchases, etc. So if someone were to man-in-the-middle that traffic, it would be captured by 33mail in a “safe” environment.

    Thanks again for a wonderful service!


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