cpanel sending bounce messages instead of 5XX errors for over quota accounts


May 9, 2013
cPanel Access Level
Root Administrator
How do I reject messages at smtp time when an email account is over quota. I don't want to send backscatter / fill my queue with undeliverable email.

Bonus points for rejecting when the main account is over quota as well.


Staff member
Apr 11, 2011
Hello :)

You can disable the following option under the "Mail" tab in "WHM Home » Service Configuration » Exim Configuration Manager" if you want to prevent the bounce email from sending out:

"Bounce email for users over quota"

This option was renamed per internal case number 51362. Here is a quote from that case:

Exim does not inherently support rejecting email at SMTP time for quota violations. This is due to the nature of SMTP transactions and the extent of Exim's knowledge of the email at SMTP time. The "size" of the email can only be known after it's accepted fully, and therefore Exim only provides mechanism to reject based on quota after acceptance (not during the SMTP transaction).
More information on this is available at the following third-party URL:

aCaB :: bit fragments » Blog Archive » Prevent exim backscatter by checking maildir quotas at smtp time

Thank you.