Setting Mail Server Hostname

The Situation

You send email from your application. You don’t want to end up in someone’s spam box.

The Fix

This is not always an easy problem to solve. We’ll start with the easiest step.

Sendmail

On your server, edit /etc/hosts. The last line should have the public IP address of your server. Add the domain name that you send mail from in front of the railsmachina name, like this:

<your public ip>        mail.yourdomain.com   your_account.railsmachina.com

Then restart sendmail:

sudo /sbin/service sendmail restart

Postfix

Edit the myhostname variable in /etc/postfix/main.cf:

myhostname = mail.somedomain.com

Then restart postfix:

sudo /sbin/service postfix restart

Testing your setup

From your server, you can test by running

telnet localhost 25

The mail server should identify itself as mail.yourdomain.com.

If you still have problems with email being marked as spam, you can create SPF records in your DNS, or you can set up DKIM.