Configuring Gmail as a Sendmail email relay

In this article I will show how to configure gmail to be an email relay for your linux server with sendmail MTA. This allow you to send letters from your bash scripts, hosted website or from command line using mail command. Other examples where you can utilize this setting is for a notification purposes such or failed backups etc. Sendmail is not the only Mail Transport Agent that can be configured to use gmail account Postfix, exim , ssmpt etc. can be configured as well. The guide below was created on Debian.

Software Installation

Create Gmail Authentication file

You can use any text editor you like instead of vi. File can have any name, in this example the name is gmail-auth:

Replace the above email with your gmail or google apps email.

Please note that in the above password example you need to keep ‘P:’ as it is not a part of the actual password.

In the next step we will need to create a hash map for the above authentication file:

Sendmail Configuration

Put lines bellow into your configuration file right above first “MAILER” definition line:

Do not put the above lines on the top of your configuration file !

In the next step we will need to re-build sendmail’s configuration. To do that execute:

Reload sendmail service:

and you are done.

Test Configuration

Now you can send an email from your command line using mail command:

If you will experience substitutional delays after executing the above command to most likely cause is that you have not configured your host with FQDN.  Check your logs for a warning:

Sendmail: “unqualified hostname unknown; sleeping for retry unqualified hostname

Want me to do this for you? Drop me a line: itgalaxyzzz {at} gmail [point] com