Getting the local IP address of a machin

[Anon]

I am storing the IP of the machines that use my system. I use the IP and a combination of another unique identifier to check whether a user has evaluated a certain class.

I am using the $REMOTE_ADDR variable to get the IP, however, it gets the IP of the gateway (all the machines are behind an ISDN line) rather than the local LAN ip.

How do I get the localhost IP rather than the router/firewall IP?

[toma42]

You can't. This is a feature of firewalls and routers.

[Anon]

even if you could get the ip of the machine behind the firewall, it would be pointless since those machines are probably on a protected lan with ips like 192.168.1.x. most lans use this ip range so you could have 30 different machines on 30 different lans with the ip 192.168.1.100.

use cookies. just assign an incremented number and send them a cookie.

-frymaster

[Anon]

I realize that a firewall prevents access to the machines behind it.

It is NOT pointless however since it is a controlled environment and only meant to be accessed by about 10 machines, not the general internet public.

We cannot use cookies since our systems are setup not to accept them since they are shared machines.

I guess I'll just have to rethink the entire database interaction and unique identifier choice. I guess sessions will be the way to go.

[Anon]

Use sessions. It doesn't matter how many or how few machines, or how authorized you want them to be, if they're behind a masquerading gateway/router/firewall you aren't going to be able to find out their IP address.

[Anon]

You CAN get the local IP with an Java Applet! Look at http://reglos.de/myaddress