Hi Experts, my server as a DC run with Windows 2000 SP2 on IBM netfinity 5100 series, serve as DNS, DHCP. occasionally it loss network connection. I cant reach any host within same segment, by ping them. Get respond by ping its loopback and IP address. If I disable & enable the network connection then no problem to ping any host. Any idea what can be the cause of this problem, which TCPIP layer and ways to trouble-shoot and solve this problem. many thanks.