Email Deliverability is a tough, yet important subject when you try to send emails from your website. We’ll try to summarize the most important stuff here!

The Problem

A majority of email messages on the Internet are spam. Therefore most email servers that receive email inspect those emails more or less aggressively in order to determine if they are spam. If they decide it’s spam, the email won’t be delivered to the recipient.

You may need to take some measures to ensure that your users receive the emails sent out by b2evolution.

The Solutions

Make sure your SMTP server is not blacklisted

This means your SMTP must NOT be configured as an open relay. Once you’re positive about that, check a blacklist monitor like https://mxtoolbox.com/blacklists.aspx . If you’re blacklisted, resolve your status with all blacklists before thinking of sending email newsletters.

Configure a working return path email

At least you will be notified when the emails don’t arrive.

You can also configure b2evolution to auto-analyze email received on the return path mailbox (POP/IMAP Settings: to Decode Returned Emails).

Configure the SPF record of your domain

Your web host or domain provider can help you with that.

Use this tool to verify your SPF record: https://mxtoolbox.com/spf.aspx

Configure your Reverse DNS

The reverse DNS name for the IP sending your emails should not be an automatic hostname from your hosting company with sequential numbers in the naming convention. This would be a huge signal used to detect quickly set-up spam servers.

Configure your SMTP banner.

Your mail server should present itself with the same name as the Reverse DNS.

You might want to change your hostname in /etc/hosts and make sure /etc/hostname is not conflicting, then reconfigure your email server. On Debian use dpkg-reconfigure exima4-config.

You can check that your SMTP banner is properly configured with this tool: https://mxtoolbox.com/diagnostic.aspx

Use DKIM

Domain Keys Identified Mail lets you claim responsibility for the emails you send by digitally signing them. This is done in your mail server configuration.

Testing

Create test accounts with the main email providers you will be sending to (you can check the stats of your user base) then using the campaign preview screen to manually send a test message to each of these test accounts. Does it arrive? In the Inbox or in the Spam folder?

You can also send a test message to a service like http://www.mail-tester.com/ - This is great for pointing out problems like misconfigured SPF records.