Hello,

Its quite well known to all that in server's WHM, there is an option that allows you to set the Maximum amount of emails a domain can send per hour, which is a great way of reducing spam/mass emailing. This feature is located in the Server Configuration option, under Tweak Settings option, under the emails listing. The option looks like as follows:

Code:
The maximum each domain can send out per hour (0 is unlimited)
Alternatively, you can change the default maximum emails per hour by updating the file via SSH accessing the server.

Code:
[root@server ~]#vi /var/cpanel/maxemailsperhour
What if you or your clients want to send emails more than the default server side settings for specific domains...

Yes its possible, though its NOT ALLOWED and never been done on Shared Hosting and Reseller Hosting.

However, it's possible to customize such setting on VPS hosting/Semi-dedicated hosting/Dedicated hosting ...!

Here we go for the same....

Make sure you login as root in server, then run the following command which will open a blank text editor, with only the following entered inside of it:
Code:
[root@server ~]# vi /var/cpanel/maxemails
# If you update this file you must run /scripts/build_maxemails_config
Go ahead and type the following (Enter domain name for what you need):domain.com=value (Where it says value, enter the number of maximum emails that particular domain can send) say for example:
Code:
[root@server ~]# vi /var/cpanel/maxemails
# If you update this file you must run /scripts/build_maxemails_config
emails.com=500
domain.net=1000
Now, as per the original document stated, we’re going to have to run a command before the actual changes take effect. So after successfully exiting the text editor, go ahead and type the following:
Code:
[root@server ~]#/scripts/build_maxemails_config
After this command, you should be ready to go! Although it doesn’t appear to do anything, it sure makes those changes happen.

A file automatically get created under the directory [var/cpanel/maxemailsperdomain/]with the email value you've set for those particular domains.
Just to check, type the following which should return the value that you entered in the previous file.
Code:
[root@server ~]#cat /var/cpanel/maxemailsperdomain/emails.com
500
Congratulations.. You have done it.. !

Important:: Make sure that you are not setting the number of emails for your domains to a very high value as it might blacklist your server IP address to some email service providers like Yahoo, Hotmail, AOL etc..