Postfix sending 5.1.1 bounces

Hi all,

I’m having a little trouble trying to configure my Postfix installation to NOT send bounce messages when someone tries to email a non-existent recipient.

From all that I’ve read this is relatively simple to set up but I don’t know if something is getting in the way (Procmail / Virtualmin?).

I have a typical Webmin/Virtualmin setup with a number of domains, Postfix handling mail and Spam Assassin and ClamAV running on certain domains.

I’ve tried manually editing the configs based on a few posts I’ve seen on the internet regarding this problem but I can’t seem to get Postfix to return a 5.5.0 during the SMTP conversation and it always instead returns a 2.5.0 and then later sends the 5.1.1 bounce email.

The page below shows my postconf output:

http://martincaine.com/postconf.txt

From what I’ve read, all Postfix has to do is look up the list of actual allowed users via the local_recipient_maps variable, and if a user is not found it should return the 5.5.0 code as part of the SMTP conversation. I’ve tried a number of values for this variable however and I think some other configuration directive may be interfering with this process:

#local_recipient_maps = $alias_maps #local_recipient_maps = proxy:unix:passwd.byname $alias_maps #local_recipient_maps = $virtual_alias_maps local_recipient_maps = $virtual_mailbox_maps

None of these seemed to make a difference. Please can someone point me in the right direction with this as it’s causing backscatter which I would like to wipe out.

Thanks,
Martin

I managed to sort this out. Turned out it wasn’t the config that was causing the bounces. I had an ‘All Mailboxes’ alias set up… but no options had been selected (so it wasn’t set to forward, retain, bounce etc… and it seemed to have defaulted to just bouncing all emails.

We are having our incoming emails to bad addresses bounce wtih:
Delivery to the following recipient failed permanently:

xcde@ourdomain.com

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 5.1.1 xcde@ourdomain.com: Recipient address rejected: User unknown in virtual alias table (state 14).

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This is backscatter essentially and we don’t have any aliases configured. How do we tell the server to stop sending back these emails? I am totally confused and we are getting blocked by AT&T as some spammer is hitting our server and we keep rejecting back to the forged address. Please help.