When you send email via script, you can specify any email address in from address. If you specify other domain in from address, it is possible that your email may be flagged as spam and sometime your email may be rejected as well.
You may receive the following error while sending the emails via script:
Failed Recipient: firstname.lastname@example.org
Reason: Remote host said: 550 5.7.1 Unauthenticated email from yahoo.com is not accepted due to domain’s
5.7.1 DMARC policy. Please contact administrator of yahoo.com domain if
5.7.1 this was a legitimate mail. Please visit
5.7.1 http://support.google.com/mail/answer/2451690 to learn about DMARC
5.7.1 initiative. s4si7418430oev.81 – gsmtp
You receive the above error when you have specified Yahoo.com or other domain’s email account in the from address. Due to DMARC policy, your email will be rejected by the recipient mail server.
Sometime you may require to receive email reply at your Yahoo or other domain. In such event, you should specify “Reply to” address in your script.