PostFix Configuration "Sender Address Change"

[abidfsd]

Dear All,
I have a question regarding postfix configuration.

I have a mail server configured via postfix on centos. If an authorize user send email through command prompt he is able to change "from address/sender address" and can send email. I want to block this capability. i am expalining the problem point wise as below.

• I have an authorized e-mail user by the name abc@xyz.com
• It logs on at mail server through console by providing his credentials (uername/password)
• after authentication he create a mail and change sender address from abc@xyz.com to klm@xyz.com and sends the mail to another legitimate user nop@xyz.com
• In nop@xyz.com inbox the mail appears to be came from klm@xyz.com instaed of actual sender abc@xyz.com
  Kindly advise how change of "fro/sender address" can be blocked.

Regards

 

[Ithariel]

I don't think there is a easy way in Postfix to block this. But you could try out some policy deamon. For example you could use postfwd which should be able to block mismatching sender/login adresses.

 

EDIT: seems there is a simple way: http://www.postfix.org/postconf.5.html#reject_sender_login_mismatch