in reply to Re^4: Identifying clients
in thread Identifying clients

At some places--for example where I work--there are multiple redundant HTTP proxy servers. So the IP address may be different on each request.

This also happens (or at least used to) with AOL users.

Plus, most people use dynamic IP addresses, which change from time to time. Even though it may be just once a month or so, the user may be confused if they suddenly have to log in again. If they're completely blocked ... well, don't do that.