My previous question got closed as those people did not quite understand my question.
I have a computer that hosts multiple domains. I have another computer that hosts another some other domains. Some of those domains are on both computers.
There IP addresses (both computers have multiple IP addresses) are unique to a particular computer.
A sub-domain only exists on one computer.
e.g. news.bbc.co.uk lives on computer A
weather.bbc.co.uk lives on computer B
The domain being bbc.co.uk.
So the question is from news.bbc.co.uk -> how do I find the domain bbc.co.uk in PHP?
try using parse_url function in php for getting domain name
also check this previosuly answered link
Get domain name (not subdomain) in php