Your cPanel control panel is accessible via any of the following links:
Your WHM (WHM is only available for reseller, dedicated and VPS clients).WHM is accessible via any of the following links:
Your control panel/s run on ports 2082 (cPanel) and 2086 (WHM). So, if you are behind a firewall or proxy server. You might have trouble accessing your control panel if that port is block. Unfortunately, there is no way around this and the only resolution is to talk. To your Network Administration about opening up that port for you.