[PHP-DEV] $REMOTE_ADDR subnet consistency? From: Nathan (nathan <email protected>)
Date: 06/29/01

Hi PHP heads,
            I have question regarding $REMOTE_ADDRes consistency. I am
developing a custom session library and I need a way to uniquely
identify each http client. Hasn’t this has been a never-ending struggle
for web developers? Anyways, I’m using the variables $HTTP_USER_AGENT
and $HTTP_ACCEPT_ENCODING to help create the session hash and am now
considering putting $REMOTE_ADDR into the pot. I know that there are
problems with $REMOTE_ADDR, like proxies and NATs, BUT I WAS WONDERING,
and now here comes my question, do the first two subnets of an IP
address (i.e. 204.57.x.x) typically stay the same, so that they could be
relied upon for general authenticity? By grepping through the access
logs this appears to be true. Ok and don’t tell me, “Why don’t you just
use cookies?” Because we must support non-cookie clients and cookies are
not as authentic as ip addresses. Thank you for your brilliant insights
to this question.
 
Nathan Cassano
ContractJobHunter
Web Developer