i am operating a cyber cafe which contans 60pcs, recently we are facing a strange ip conflict problem in our network,and after the ip conflict, the gateway of the network will also shutdown.When i restart the conflict PC,the IP is reset to 0.0.0.0.When i turn off my 3COM 2250 switch,everything become normal.I dindt set any DHCP in my network,i assingn static IP for all the PC However we already make sure that the network do not had any duplicated ips. Any thoughts guys?

I would ARP scan the entire network to verify you don't have a PC with alternate settings, or a PC that's losing its settings. Do all machines have a unique MAC address?

Then scan the entire LAN when the conflict occurs and see what machines show up.

J.
j e r u v y a t y a h o o d o t c o m

staticly route your IP through your computer TCP/IP settings. CHoose a different IP address than is on any other LAN object like 192.168.0.255 or soemthing of the sort. If it still has a conflict, do what the Jeruvy sugested.

I'm here to help as best I can...