Postfix - bounce for 450 code

[mattko]

Hello Gents!

I have strange issue, as I am newbie in postfix and I am trying to solve this particular one scenario:

I need to send bounce message immediately to user when the recipient domain does not exist, I have restrictions set to reject such message with reject_unknown_recipient_domain option, server drops it and sends mail to postmaster with specified action, but not to sender;

I tried to do it with unknown_address_reject_code = 550; but in this case there is still no bounce and the only thing that changed is code, from 450 to 550

below is configuration which I am using now for recipient,
[pre]# Recipient restrictions
smtpd_recipient_restrictions =
reject_non_fqdn_recipient,
reject_unknown_recipient_domain,
check_recipient_access hash:/etc/postfix/acl_recipient_checks,
permit

unknown_address_reject_code = 550[/pre]

looking forward to some solutions for this case,

Thanks
Mattko