As you may know from my previous post, I recently made the switch to Digital Ocean for my VPS needs. So far, everything has been great. However, I encountered a problem the other day regarding Reverse DNS (rDNS) for my VPS. The error occurred when I attempted to send an email to someone with a @cox.net email address. I got a reply containing a failure message. The message contained details about an invalid rDNS name.

After searching the Digital Ocean forums, I learned that by default, Digital Ocean configures rDNS for all hosting accounts. I couldn’t, for the life of me, figure out why mine was not working.

Then I read a small post that stated something along the lines of

In order for rDNS to be configured properly, the name of your droplet must be the same name as the URL that is being used to point to the droplet’s IP.

After changing the name of the droplet to reflect the primary domain name, everything worked out and emails started sending.

So now you know: Name your droplets with their corresponding URLs.