IP Address Function

[Nobody]

On Wed, 08 Jul 2009 20:53:12 -0700, Fred Atkinson wrote:

>>ipaddr = (getenv("HTTP_CLIENT_IP") or
>>      getenv("HTTP_X_FORWARDED_FOR") or
>>      getenv("HTTP_X_FORWARDED_FOR") or
>>      getenv("REMOTE_ADDR") or
>>      "UNKNOWN")
>>
>>print ipaddr
> 
> That did it.  
> 
> I wonder why they don't just have a function to return it instead of
> putting you through all of that?  

There's no unambiguous definition of "client IP", so you have to choose
which definition you want.

REMOTE_ADDR is set to the actual IP address from which the connection
originated (from getpeername()). If the connection was made via a proxy,
REMOTE_ADDR will contain the IP address of the proxy.

The others are set from HTTP headers. Proxies often add Client-IP
or X-Forwarded-For headers to indicate the originating IP address. OTOH,
there's no way to know if the headers are accurate; nuisance users may
add these headers to confuse poorly-conceived banning mechanisms.