On 06/07/10 22:48, Les Mikesell wrote: > Chan Chung Hang Christopher wrote: >> Christopher Chan wrote: >>> And now the thing is working again... >> >> It's not working again. >> >> Running tcpdump -i vlan seems to trigger something to get the network >> working again but as soon as I stop tcpdump...nada, zip, zilch. >> If you have two machines on the same network with the same IP address you get behaviour like this. Had this happen once when an engineer reset a UPSs and it took on the IP address of a main switch. arpwatch is your friend. K