I have dnn installed on a hosting cloud with a company named MOSSO (a division of Rackspace)  Pretty, all is well, except that the site log show the same IP address for everyone that logs in.  After some brief investigation, I found that the IP address that is shown is actually the IP of the load balancer they use.  They offer a work around for this below:

Here it is:

According to item #5 on this page, the variable you want to replace "REMOTE_ADDR" with is actually "HTTP_X_FORWARDED_FOR" (perhaps either will work?)
 
Anyway, the DNN reference you're looking for is contained in file "default.aspx.vb" in your site's root folder.  Open the file and do a search for "addsitelog".  The specific reference you need to change is the passed stored procedure parameter "Request.UserHostAddress". 
 
Hope that helps-
-mamlin

Thank you for the tip.  I went into default.aspx.vb and found the addsitelog area.  I then replaced "Request.UserHostAddress" with ("Request.ServerVariables("HTTP_X_CLUSTER_CLIENT_IP") and it worked.  I tried using HTTP_X_FORWARED_FOR but that did not work.  I also think DNN Corp needs to take a look at Oliver's code below and consider using it as a fix.  Cloud hosting  seems to be a growing phenomena and I think his code takes that into account when IP tracking is relied up.  My company uses IP tracking as a security mechanism to limit the number of IP's clients are allowed to use at login....so we really need the client machine IP's at login to make our security application operate.  Thank you for your help. I will post this fix on my website.
 

Thank again,
Bill Shoap
Work Smart Data Systems
www.worksmartdatasystems.com