The initial matter that I was referring to was whether an IP address is likely to change in the middle of a session, and I get the impression that it will not change. An AOL user would probably have to log off AOL and then log back on again to get a new IP address.

However, IP may be deficient for certain types of session management schemes even if there are no proxy servers involved. For instance, what if I log onto a website twice concurrently from the same machine?

It is surprising to me that cookies need to be used in session management for anything more than caching a password, but apparently a lot of people are using them.

I am glad you like the dog picture on my website. It is actually a picture of me with my new French girl friend Fanette who I met in Brittany last year. Fanette is a purebred dachshund whereas my companion Sierra the Dog is half doxey.