how to identify each user behind the NAT router?

identify user log track nat

[clement]

assuming these are business/office users behind a NAT router,
and cookie can only associate to one site mostly,
yet we want to do log analysis over many sites
so to track which sites user went from the logs,
the problem is that I could not know whether one is the same user or not from different sites' log, since they all use same public IP as result of NAT.

how do we solve this problem, appreciate any helps!

[larryn]

Clement,

You could try the dredded and often foiled third-party cookie, but that would be frequently foiled. If the sites are self-referring to each other, you could look into URL rewiriting so that the links between sites incorporate a unique identifier that is used at all the sites.

For example: instead of site A using a link that sent someone to:

 www.siteb.com/index.html 

site A would code that link as:

 www.siteb.com/index.html?uid=siteAuniquieID 

You would have to dynamically change each of those links as the page is re-written which is something that can be readily (but not without some work) done on an Apache server. And then you would need to extract the unique ID from the URL to do your analysis.

Hope this helps,

Larry

[clement]

Thanks Larry,
unfortunately we can not access/change each sites' design(own by each different publish company), although we can ask for info. we need to help analyse their log.

The problem is the IP address is same after NAT router for all the users,
just wondering how to distinguish each of them so to see which sites they visit.

[larryn]

Clement,

Basically, trying to coordinate information between sites is against all the privacy protection built into the browser. Without doing something 'extra-ordinary' that would have to manifest with the way links are handled, you really don't have sufficient data to mix and match.

I was thinking if the individual sites captured clickouts you could look for clickouts from one site and a landing at another site, or just use the referrer to get a rough count, but then you won't have individual data (again back to privacy).

But perhaps you are expecting something from analytics that isn't really its domain - analytics are about trends, not individual details.

Good Luck,

Larry

[ytswy]

There was a story on slashdot [yro.slashdot.org] a little while ago which covered something like this. Basically you persude the browser to cache a file containing a unique id, and use that to track the individual user.

It's not a particularly nice technique IMO, and may well irritate a portion of your users. If people have third party cookies turned off they generally don't want to have their behaviour tracked across multiple sites.