Quick question regarding FCrDNS

[ovizii]

I've gotten a bit confused here, can someone please help me figure out what exactly is checked when a FCrDNS is done?

i.e. I am sending an email to recipient A. When A checks my server's FCrDNS does it check simply based on the IP I am sending from or does it take into account what's inside my /etc/postfix/main.cf under myhostname?

Can someone point me towards a proper explanation or graphical illustration?

[pdwalker]

FCrDNS?

[ovizii]

forward confirmed reverse DNS.

I think I've figured it out. Apparently the recipient receives my hello, then does check if there is an A record pointing to the IP I am sending from. After that it checks if there is a PTR record for the sending IP returning the hostname I announced via the helo. and the previous step.

Please correct me if I am wrong.

[pdwalker]

Yes, your understanding appears correct.

It is important for mail servers to have their reverse dns setup correctly and matching the forward dns entry, or else quite a few mailservers will just reject the mail.