Hello,

I am using sendmail for my mail server. Undelivered message bounce back to the postmaster with the body of the message. However, I dont want this to happen; senders should get the undelivered notification. I am not sure about the changes I have to make to the sendmail configuration for this.


thank you for your time , any suggestions are welcome

Regarsd

I think the default used to do that, but hackers could exploit it to test for mailboxes. So, this setup should be only on intranet hosts, not Internet exposed ones. The rewrite rule sets in sendmail.cf are not for the weak of heart. Overview of Configuration Files Riley wrote one of their thickest books on it. Many competing mail servers with gui configuration have sprung up to compete with the default. I found a reverse tip, something maybe you can undo: Sendmail rewrites email address to send to the local machine instead? - Server Fault
Added define(LUSER_RELAY',local:root')dnl to return undeliverable mail to unknown users to root instead of to sender, per serverfault.com/questions/274211/sendmail-dsn-user-unknown – sapark Oct 6 '11 at 18:51