Tableau 2018.2 Linux No 'Enable TLS' Option & Gmail - Postfix Workaround

Issue

Tableau Server (2018.2.0 on Linux) does not support TLS (or SSL) for SMTP. If you want to use smtp.gmail.com port 587 to send out subscription and server notifications, then you may be stuck.

What Other People Are Saying

You “may be stuck”, because seemingly some people have an option in Tableau SMTP config to Enable TLS. If you have this option, then I suggest you use it, otherwise read on!

Diagnosis

Firstly, check that the SMTP settings are correctly configured and it’s the lack of TLS that’s the actual issue. Subscribe yourself to some content, then go to the Schedules tab, select the schedule you subscribed with and click on the Run Now button (it looks like a “Play” arrow).

Go to the Status tab and select Background Tasks for Extracts. Adjust the Task filter so it’s only showing Subscription Notifications. There should be a red cross corresponding to the time that you selected Run Now on the schedule. If the data for that cross includes Must issue a STARTTLS command first, then a lack of TLS is your issue.

Workaround

The workaround is to setup a mail relay on the Tableau machine itself, this should be one that will only accept mail from the local machine and use TLS to connect with Gmail.

If you’re on CentOS 7 or similar (Amazon Linux 2) then you can follow this guide, just be sure to restrict usage to the host only. According to Postfix’s docs then this is the default in 3.0+. If your yum installed 2.10.1 like mine, then add mynetworks_style = host to /etc/postfix/main.cf (full explanation in the docs).

Once you can send mail from Postfix on the machine (check your Junk folder), set Tableau’s SMTP config to point at localhost and port 25, with no user or password. In your terminal on the machine sudo journalctl -u postfix -f to follow the log, then hit the Run Now button again on a schedule and see what happens.

If you get a message back from Google in the logs about signing in via a browser and trying again, be sure you’ve turned allowed less secure apps for the email account. This last bit could possibly be worked around by using a different mail relay or reconfiguring Postfix (I’ll update if I find a way), but this is at least more secure than Tableau’s native no-TLS stance!