I'm using a third party mail server to receive/send emails for the domains hosted on the VPS. They provide MX, TXT, CNAME records (without any IP address) to add in the DNS zone file for each domain, which I did successfully and emails are being sent by the PHP script using SMTP authentication.
Thus, I have disabled all email related services (Postfix, Dovecot, etc.) on low resource CentOS 7 VPS. As a result, I'm not getting system emails like SSH login alert, IP block, etc. from LFD + CSF.
I want to receive these system notifications and by searching on the internet, I have come to know that I've to continue Postfix MTA and convert it as a send-only SMTP server.
However, is there any option to send system alerts using SMTP authentication without the Postfix? If yes then what do I need to configure exactly?
Additionally, I have checked the Reporting Settings in the Firewall configuration but couldn't understand how do I perform LFD/CSF to send these emails using third-party SMTP authentication for the primary domain name.
Can anyone please assist me to send System Emails without Postfix MTA on VPS? I'm using CentOS Web Panel to control hosting.