Mail-tester.com: HELO does not publish an SPF Record

#1

I have followed all the tutorials to build my own ubuntu web server from scratch and am successfully running a web server. In my mail-tester.com test, i get a 10/10. However, it looks like one single thing could be improved, and I am not sure how to fix it. Mail-tester.com gives me the following improvement message:

-0.001 SPF_HELO_NONE SPF: HELO does not publish an SPF Record

What exactly does this mean and how can I fix it so that HELO publishes an SPF Record?

#2

you have to check SPF Record where you configure the dns for sure and them error ip and static and always that
Reverse DNS lookup (rDNS) and just what version of linux you are using

#3

I believe it’s suggesting that you should create an SPF record for your Postfix hostname (mail.example.com).

You already have an SPF for the apex domain (example.com).