Two variables are useful for identifying the connecting client:
  1. REMOTE_ADDR
    This is always the IP address of the connecting client.

    For this connection, the value is:
    REMOTE_ADDR =

  2. REMOTE_HOST
    If the IP address of the connecting client (typically, where the browser is running) can be resolved into a hostname, then this variable is set to that value. If the resolution fails or if Apache's HostnameLookup directive is set to off (a good idea when request time performance is critical), then the value will just be the IP address itself (ergo, the same value that's assigned to REMOTE_ADDR).

    For this connection, the value is:
    REMOTE_HOST =