It would be great help if someone could help me with this:
I want to restrict ‘To’ field to have only a few particular domains for security reason, e.g., outgoing emails will be allowed if those are sent to only @domain1.com and @domain2.com; all other emails will be blocked.
I could not see any option in the SMTP plugins. Will I have to add any filter to wp_mail function? Any lead will be helpful as I am a newbie to WordPress programming :). Thank you.