kpjlfm writes: "I'm asking for guidance (or a solution) to a one-off problem. I have to isolate three devices from the rest of the network, but allow packets from one pc on the rest of the network sent to device #two (UDP using port 10000), using a 3Com 4500 switch. I don't normally do this, and probably won't do it again (or for years). Rather than reinvent the wheel, can someone with experience using the 4500 switch tell me if this is possible. I read the manual, sort of, and I'm thinking I should be able to accomplish this with ACL to deny and allow, but I can't figure the correct syntax."