Ubuntu Server quick help

Hi, I'm still an Ubuntu Server newbie and this is my problem. I've installed a fresh Ubuntu Server on my old PIII for testing and I just have two workstations that will be used with it. All three machines connect to an 8-port switch and the switch in turn connects to a Wimax modem. I've installed everything on the server (I think) and even got the Internet working with it. But I CANNOT ping the other machines, nor can the server be pinged. I can't figure out the problem and I'd like some help on resolving this. Bidders, please bear in mind that I ain't an expert on this thing but I've done this enough and more times in the last 15 years on Windows. Also bear in mind that the winning bidder will be expected to walk me through the commands telling me what is being done and why. We can use the RAC chat for this. Many thanks. ## Deliverables The winning bidder should help with the following: 1. Give me instructions that I can understand and follow on a real-time basis to get my LAN working. 2. I don't need any service like LAMP servers, etc. I just need the machines to communicate. 3. I'm not even concerned about getting the Internet connection on the server as I already have this done. ## Platform Ubuntu server 8.04.1 LTS Windows XP Professional as clients.