Sendmail Delivery errors plugs up the queue
 

Hi,
I get many error messages from the MAILER-DAEMON due to spammers, that send mails to non-existent users, making the sendmail's queue full. How can i impede the delivery of those messages or how can i delete them?

Maybe start by doing an open relay test (online, easy to find), force TLS on submission (or see any HOWTO concerning "SMTP auth"), use blacklists in your sendmail config (search for RBL), deploy spamassassin or mailscanner and use "iptables -m recent" if your clients never exceed a certain rate of sending emails?

Deferred:
 

I wanted to solve the problem making a script that deletes the messages in the queue that have for subject "Deferred:".
I can't modify the configuration because it's integrated with Scalix and it's a complicated thing.
Another possible solution could be disabling those type of messages...
Any ideas?