CPanel Proxy - WHM Proxy Domain

What is CPanel Proxy Support?

CPanel proxy support allows you to access both the domain.com/cpanel and domain.com/webmail as subdomains. Additionally the normal CPanel ports for both the control panel and webmail are proxied through port 80. There are quite a few firewalls that block 2082, 2083 et. cetra as they are not standard ports.

The following once enabled should work:
http://cpanel.domain.com
http://webmail.domain.com
http://whm.domain.com

Requirements
CPanel
mod_rewrite
mod_proxy

How to enable CPanel Proxy

1. Open the WHM and access tweak settings:

Main >> Server Configuration >> Tweak Settings

2. Enable the following options:

Add proxy VirtualHost to httpd.conf to automatically redirect unconfigured cpanel, webmail, webdisk and whm subdomains to the correct port (requires mod_rewrite and mod_proxy)

Automatically create cpanel, webmail, webdisk and whm proxy subdomain DNS entries for new accounts. When this is initially enabled it will add appropriate proxy
subdomain DNS entries to all existing accounts. (Use /scripts/proxydomains to reconfigure the DNS entries manually)

This will setup all new accounts with the proper records; existing ones will need to be added via the /scripts/proxydomains script.

I would recommend disabling this one as you probably don’t want a client to break the setup for their domain trying to fix it:

Allow users to create cpanel, webmail, webdisk and whm subdomains that override automatically generated proxy subdomains

3. For existing accounts open a shell prompt as root. All you need to do now is to setup the sub-domains so that customers can access them. The best way to do this is to specify the username:
Example:
/scripts/proxydomains --user=username add
Usage:
/scripts/proxydomains --user=mycpaneluser add
To do all accounts on the server (which can take a while):
/scripts/proxydomains add
To list all the options for this script simply type
/scripts/proxydomains 

4. Add this to httpd.conf

# CPANEL/WHM/WEBMAIL/WEBDISK PROXY SUBDOMAINS
<VirtualHost xx.xx.xx:80 *>
    ServerName $hostname
    ServerAlias cpanel.* whm.* webmail.* webdisk.*
    DocumentRoot /usr/local/apache/htdocs
    ServerAdmin system@hostname
    <IfModule mod_security2.c>
        SecRuleEngine Off
    </IfModule>
    UserDir disable
    RewriteEngine On
    <IfModule core.c>
        SSLProxyEngine On
    </IfModule>
    RewriteCond %{HTTP_HOST} ^cpanel\.
    RewriteCond %{HTTPS} on
    RewriteRule ^/(.*) https://127.0.0.1:2083/$1 [P]
    RewriteCond %{HTTP_HOST} ^webmail\.
    RewriteCond %{HTTPS} on
    RewriteRule ^/(.*) https://127.0.0.1:2096/$1 [P]
    RewriteCond %{HTTP_HOST} ^whm\.
    RewriteCond %{HTTPS} on
    RewriteRule ^/(.*) https://127.0.0.1:2087/$1 [P]
    RewriteCond %{HTTP_HOST} ^webdisk\.
    RewriteCond %{HTTPS} on
    RewriteRule ^/(.*) https://127.0.0.1:2078/$1 [P]
    RewriteCond %{HTTP_HOST} ^cpanel\.
    RewriteRule ^/(.*) http://127.0.0.1:2082/$1 [P]
    RewriteCond %{HTTP_HOST} ^webmail\.
    RewriteRule ^/(.*) http://127.0.0.1:2095/$1 [P]
    RewriteCond %{HTTP_HOST} ^whm\.
    RewriteRule ^/(.*) http://127.0.0.1:2086/$1 [P]
    RewriteCond %{HTTP_HOST} ^webdisk\.
    RewriteRule ^/(.*) http://127.0.0.1:2077/$1 [P]
    UseCanonicalName Off
</VirtualHost>