We currently have a method in Geo UDF that takes an IP address from the
remote host header and the X-Forwarded-For value and attempts to identify
the originating client IP address by following a simple algorithm as
follows:
GetClientIP(remote_host, X-Forwarded-For)
IF X-Forwarded-For value is not valid:
return remote_host
ELSE:
FOR EACH valid IP address, proxy_ip, in the comma-separated
X-Forwarded-For value:
IF proxy_ip does not start with "127.0" or "192.168" or
"10."
or "169.254":
return proxy_ip
What are the ways in which this naive algorithm can be improved? For
example, is it better to maintain a separate list of IP address to ignore
(currently only 4)? If yes, how do we ensure that the list is exhaustive?
Any other improvements?
Thanks,
Ananth