Would two users on the same machine (internal corporate computer) generate the same IP number? I think yes.

I have read posts from two "friends" and "collegues" who used the same machine the same day, they say, yet the IP checker is not catching this occurance. Is the IP checker being reset daily so that if a poster uses a different machine on different days they will not have the different IP address caught? Would anyone posting from home and from work then have two IP numbers?