how do I see incoming IPs to a web server?

Could someone point me in the right direction to figure out how to check the
incoming IP addresses of people who are viewing my photos on a PC based
server (Qurio.com) that's located on my Green network behind Smoothwall 2.0?

None of the out-of-box logs seem to show this, though my old linksys router
showed this stuff in its log.

Thanks for any help. I've search on various forums and can't find the way
to go. Is there a mod I need to install?

I have all SW patches up to date and the excellent Full-Firewall-Control mod
installed.