Follow-up: real ip VS firewall

[Anon]

I am noticed $REMOTE_ADDR could be used to get a user's ip. So what if a user is behind a proxy server or firewall? Will I get a 'fake' ip? Could it be possible to trace the real ip?Thank you very much.

[Anon]

Will I get a 'fake' ip? <<

Yes

Could it be possible to trace the real ip? <<

Not reliably