I have website on hosting with domain exmpl.com. I have DNS record for exmpl.com:
exmpl.com MX(10) mail.exmpl.com
mail.exmpl.com A XX.XX.XX.XX
exmpl.com TXT v=spf1 +a +mx +a:hosting.server ~all
All incoming mail recived by hosting server.
Now all mail work over hosting server. I want to create SMTP server to send-only mail. I use Postfix.
And create DNS record for exmpl.com:
smtp.exmpl.com A XX.XX.XX.XX
smtp._domainkey.exmpl.com TXT DKIM key
I have PTR on smtp.exmpl.com. How to setup spf record to send mail.
Example: i want to send mail from user1@exmpl.com to user2@gmail.com, but use my smtp server smtp.exmpl.com.
Do i need to create subdomain on hosting, smtp.exmpl.com and setup spf record for it? if yes, how to use this record in spf record of exmpl.com?
PS: SMTP server on Ubuntu 18 (This only-send SMTP server)