getenv("HTTP_REFERER") works or not?

[j_miguel_y]

Is is possible that some computers allow
geten ("HTTP_REFERER") to work while some computers allow this function to work? The reason being is because in my home computer, getenv("HTTP_REFERER") function works, but in another computer it does not work?

any ideads why?

[TheDefender]

From the manual for Predefined Variables ($_SERVER):

HTTP_REFERER
The address of the page (if any) which referred the user agent to the current page. This is set by the user agent. Not all user agents will set this, and some provide the ability to modify HTTP_REFERER as a feature. In short, it cannot really be trusted.