When do SERVER_NAME and HTTP_HOST differ?

[estelle]

Hi,

Can anyone provide examples of where $_SERVER['SERVER_NAME'] and $_SERVER['HTTP_HOST'] would differ?

The only example I've found is when running on localhost becaues I use a specific port and the two variables come out as:
$_SERVER['HTTP_HOST'] --> localhost:10001
$_SERVER['SERVER_NAME'] --> localhost

Are there occasions where one variable will be blank and the other will be set?

TIA :)

[btherl]

'SERVER_NAME'

    The name of the server host under which the current script is executing. If the script is running on a virtual host, this will be the value defined for that virtual host.

'HTTP_HOST'

    Contents of the Host: header from the current request, if there is one.


Going by that description, SERVER_NAME should be more stable, since it's defined by the web server.  HTTP_HOST will probably have more variance.

I haven't answered your question, but I hope this helps :)

[estelle]

Thanks, it does help :)

I looked up those descriptions and wasn't really sure about what to make of it.  I appreciate your opinion!  I'll start by using SERVER_NAME and then if I run into problems i'll consider checking HTTP_HOST.