PHPMail will work fine with the settings in the tutorial.
If you want to use a separate SMTP server then don't delete the MX records.
People can DDOS your mail server all they want, it won't take your site down. Lol
If you want to use a separate SMTP server then don't delete the MX records.
People can DDOS your mail server all they want, it won't take your site down. Lol