The technical side

Feel welcome to address these questions via email to Support & Customer Service | cPanel, Inc. I'll provide a brief overview here but you can request more detailed information via email.

cPanel and WHM is a single product with 2 interfaces. WHM is for the server administrator and cPanel is for the individual hosting accounts. Resellers typically have limited access to WHM but full access to cPanel.

You can compile Apache and PHP modules into Apache and PHP very easily using EasyApache. You'll find EasyApache in the WHM interface in the "Software" section listed as "Apache Update." mod_php as well as SuPHP are supported, as well as PHP running as CGI and PHP running as FastCGI.

cPanel/WHM is not itself VPS provisioning software. However, it will work within and automatically optimize itself for virtual environments.

Many applications are standard including Exim which we use as our MTA. Once cPanel/WHM is installed, you will essentially have everything you need to maintain a shared hosting server. However, you may wish to acquire billing software if you wish to automate the purchasing of web hosting on your server. I have a list of billing applications known to work with cPanel/WHM, so feel welcome to email me at Support & Customer Service | cPanel, Inc. for that list.

cPanel is predominantly written in Perl. This comes as a surprise to many because of the great performance experienced in cPanel and WHM.

cPanel/WHM is highly configurable. We have a security section in WHM where you can manage brute force protection, disable compilers, prevent fork bombing and other similar tweaks. You can make the security settings on a cPanel/WHM server as relaxed or as strict as you desire.

The cPanel interface is very easily modified and branded. In addition to a highly configurable experience, we also offer many APIs and hooks you can use to control the behavior of cPanel/WHM. Feel welcome to email me at Support & Customer Service | cPanel, Inc. with your needs and I'll assist you with how cPanel/WHM can meet those needs.

Note, sales emails will be answered far more promptly than sales inquiries posted to our community forums.