IP scan

Question: I have a lot of PC inside a LAN, with fiex IP Problem is i dont have the IP addresses, and I dont have access to all the machines. I could use PING at different times and several times to get the IPs when they are connected, but no one wants to type 255 IPs from a subnet more than once (or even once) What Linux (even better if its in SuSE 7.3 CDs) tool could i use for that? Thanks -------------------------------------------------------- Juan Francisco Torres Ch.