Really strange problem here. I have a 3560 switch split into three vlans, 1, 2, and 3. All are communicating fine, BUT my boss and I used Vista. He's in Vlan 2 I'm in Vlan 1. We can only ping each other when our Windows firewalls are ON, and we can only traceroute each other when our Windows firewall is on. Ok, not a big deal BUT: When I telnet to the switch I cannot traceroute our machines at all (with firewall on or off). Any other XP, 2000, 2000 server machine is fine, I can ping and trace them fine. The thing is, these Vista machines are directly connected to the 3560 switch, why can't the switch trace a Vista machine that is directly plugged into it? Why is Vista having a problem, but XP, 2k are all fine. We ran a sniffer on the Vista machines that the L3 switch was unable to traceroute. I noticed some messages that stated "traceroute malformed packet". Could this be causing the trace packets to die somehow? Very confused here, any help would be greatly appreciated. Thank you!