I bought a VPS Host that gave me only 1 IP Address which I used on my first domain name and it works without any problems.

Now my second domain name I can't use the same ip address as it points to the first domain name.

So I figured my only option was to use a GoDaddy hosted iframe redirection which redirects to a sub folder on my first domain which worked so far.

Now I'm trying to load paypal from <?php headers() ?> and I get a permission error because of that iframe

Refused to display 'https://www.paypal.com/cgi-bin/webscr?notify_url=&cmd=_cart&upload=1&business=removed&address_override=1' in a frame because it set 'X-Frame-Options' to 'SAMEORIGIN'.

How do I avoid the Iframe solution for my second domain while not messing up my first domain?

Somebody I forgot once told me it doesn't matter if you have 1 IP Address you could host multiple websites on it? how it that possible the DNS doesn't seem to work off ports afaik, yes I could host multiple websites on different folders but that's not what I call hosting a real website it has to be pointed by a domain name, so this iframe issue doesn't happen

My server configuration is httpd (apache) that comes with CentOS 6 (Linux) operating system