mail authentication

[alireza.mhzy]

hello
i used plesk before and for a security reason i migrate to cpanel but i think problem exists.
let me to explain.
my co-workers sets all emails on outlooks and thunderbirds at work. sometimes archly they go to for example thunderbird and changed the email address in setting and send email to others as CEO and finally everyones gets email.
how can i configure exim for block this emails and do not send any non-available addresses or not authenticated users?

 

[keat63]

If all he did was change his name and reply address, then he would still have been authenticated using his login details.

I'd suggest that the best course of action would be to restrict his access to outlook or T-Bird config.

 

[cPanelLauren]

Are they all on the same IP address? If so it sounds like the following is enabled in WHM>>Server Configuration>>Tweak Settings ->
Allow users to relay mail if they use an IP address through which someone has validated an IMAP or POP3 login within the last hour (Pop-before-SMTP)

In order to change this though as the website owner you'd need to speak to your hosting provider as it's a setting you would not have access to without root access.