Well considering you have a DHCP server i would guess ur IP address is dynamic. but still an IP address is very dangerous especially if the box is not secured.. like RiOtEr said.. it all depends on your administrator..

but once ur IP address is picked up by a malicious person, you are a target, he knows where you are, so your option is change ur ip address by either manually doing it through DOS or restarting your PC.. and relogging into the network.

As a result the DHCP server will assign you a new IP address..