Gmail takes substantial steps to prevent spam from reaching their users. This can often trip up legitimate companies who are just trying to stay in touch with their clients or vendors. How do you handle the problem of receiving this Gmail error:
Error 550-5.7.25 The IP address sending this message does not have a PTR record setup. As a policy, Gmail does not accept messages from IPs with missing PTR records. Please visit https://support.google.com/mail/answer/81126#authentication for more information
Always Have a PTR Record
First off, you absolutely should have a PTR record associated with your IP address. This ensures that a company has a definitive way of correlating a domain name on an email address with a matching IP address. It helps to ward off spam spoofers who ‘claim’ to be AOL or Gmail or something else when they are really a server in Nigeria. Every server you work with should have a matching PTR record.
It is generally not you, the web server person, who sets up that PTR record. That’s not something you can set at Network Solutions, for example. Instead, you talk with the person who is hosting your server for you. The people who assigned you the IP address are the people who can attach a PTR record to that assignment.
In my case, I host with TurnKey Hosting, and they are the ones who created my PTR records for me.
Also Have an AAAA Record
Gmail is not great with their error messages. If you get this 550-5.7.25 error, you need to BOTH have a PTR record for your server AND ALSO an AAAA record. What is an AAAA record?
Just like you probably have set up, in your DNS area, an A record and a MX record for your server, you should also have an AAAA record. Where an A record uses IPv4 format, the AAAA record uses IPv6 format. The IPv6 format is longer and offers more numbers in general for the internet to use. The internet ran out of IPv4 numbers back in 2019. Going forward, servers should report both an A record for legacy reasons and an AAAA record for works-now reasons.
There are free converters online to determine what the matching IPv6 number is to go with your existing IPv4 value.
Once you have your AAAA record, go in to manage your DNS just like you would to work with an A or MX record. For Network Solutions, for example, you view your list of domains. You choose to ‘manage’ the one you wish to work with, and edit its advanced DNS settings. There should be a big plus button to add in a new record. AAAA is one of the standard record types.
Note that Gmail also recommends setting up DKIM and DMARC records.
Ask with any questions!