I can't figure out how to get my new MacBook wirelessly online and any suggestions would be welcome. Here's the situation... I have an existing network (described below) which works fine with a couple of different Windows XP machines connecting wirelessly with Dell TrueMobile wireless LAN cards. With the MacBook I can connect to the Wireless hub but there seems to be something blocking any traffic to and from the Mac when connected wirelessly. (Wired connection to the MacBook ethernet port works fine, so I don't think it is anything to do with firewall settings on the Mac). I know the MacBook connects wirelessly since (i) on the Mac the status shows as connected, and (ii) the wireless hub logs each connection/disconnection from the Mac. However if try to ping anything in the LAN network from the wirelessly connected Mac, all I get is "Host down" or "No route to host". I looked at the network traffic using tcpdump while doing the pings and the only traffic is outbound ARP "who_has" requests. Nobody replies to the ARP requests, so of course the Mac's networking is hosed even though it is connected to the wireles hub. This screams of a wireless hub/ rest of the network configuration issue but the Windows machines connect fine in this environment so there's clearly something I haven't understood. Network diag: ADSL==Firewall==LAN switch==(via Ethernet)==Wireless Hub Firewall: OpenBSD LAN Switch: Dell Powerconnect 2224 Wireless Hub: Buffalo WHR-HP-G54 in bridge mode. It's got the latest firmware (1.38 IIRC) MacBook: running OS X 10.4.6 (also just tried 10.4.7) with an inbuilt Airport Extreme card at rev level 0.1.20 The Wireless Hub has some ethernet ports so I did try connecting the firewall directly to the Wireless hub but no difference. Any suggestions? Would you expect replacing the Buffalo with an Airport Extreme base station to work? Thanks.