Automatic reply for full email and suspended emails causing poor reputation

Hedloff

Well-Known Member
Jun 7, 2004
175
9
168
Up north!
cPanel Access Level
DataCenter Provider
I often see alot of spam mails sent to

our customers.

Some customers have their email accounts full and some have suspended for example outgoing emails.
When that email address gets a spam email, the server will then return the mail and body to that sender:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

[email protected]
LMTP error after end of data: 452 4.2.2 <[email protected]> Mailbox is full / Blocks limit exceeded / Inode limit exceeded:
retry timeout exceeded

++ body

Often emails are spoofed from sender address and since the body is returned to a user that didn't send that email in the first place it will be marked as spam.
And in some cases our servers get "poor reputation" og "blacklisted".

I asked cPanel about this, but they had no solution :-(
Does anyone have a working solution? In my opinion this is something that cPanel should use resources to find a better solution.
 

cPWilliamL

cP Technical Analyst II
Staff member
May 15, 2017
258
30
103
America
cPanel Access Level
Root Administrator
Is this regarding a specific RBL? Unfortunately, the issue of backscatter is a bit complicated. Using blackhole would eliminate any backscatter, but it could also cause issues with legitimate mail. Using ':fail:' is expressed in the RFC, but this leads to backscatter. Have you tried using Greylisting?
Greylisting - Version 66 Documentation - cPanel Documentation
 

Hedloff

Well-Known Member
Jun 7, 2004
175
9
168
Up north!
cPanel Access Level
DataCenter Provider
Yes, on :fail we have gotten it sorted as that also cause more servers blacklisted all over the place.
Greylisting is a terrible service that just caused alot of headache and pain for us and customers, so no, I will not test that again!