PHP email header for reverse DNS

Question

Context:

I've recently had my host set up reverse DNS (and PTR) to prevent my PHP generated emails from being interpreted as spam.

My questions:

1. Is there a specific PHP mail header that I should be using for the reverse DNS to take effect?
2. Is reverse DNS dependent on DKIM and SPF being enabled?

Answer 1

1. No. Reverse DNS has nothing to do with mail headers, and everything to do with the IP address that sends the messages.

2. No. But having those set up will help you too.