[exim] how to setup exim for different mail sender / account

All,

I am not good at Linux and English.

I use my raspberry pi as a webcam for security. I want the system can send email to me automatically. So I installed exim4.

I use Gmail or other SMTP service to send mail. After setup and put my SMTP account into "passwd.client", I succeed to send mail with mail command manually.

Later, after searching and reading a lot, I'm giving it up with the question below. So try mail all of you for help.

My question:

Why mails from all user accounts in system all reads from my email? how to setup to make all users with their own email address?


Best Regards
Xin