2. Joe logs in through webmail and creates five folders besides "Inbox".
3. He keeps only 5 MB mails in Inbox and keeps moving new mails that reach his inbox to folders created by him.
4. Over time each "new folder" grows to around 20 MB. Five new folders created by him are using 20*5 =100 MB storage.
5. WHM/Cpanel does not take into account the new folders (created by Joe) when calculating quota. Therefore Joe can store 100 MB or unlimited mails in his mailbox that was originally allocated 10 MB space.
cPanel support response to this issue is:
"The quota only applies to mail that is in the inbox. So while the total usage including mail saved in numerous folders is above the quota, it doesn't actually get enforced until that amount is surpassed by only the contents of the inbox folder."
In a nutshell, the above means that every mail user on WHM box can have unlimited storage beyond the mail space allocated by site/server admin to the user ??? Please help.