The latest firmwares for WRT54G ver 5 or 6 (firmware ver 1.01.0) and wrt54gs (not sure of which versions) (firmware ver 1.50.9) seem to have problems providing IP addresses to Mac computers via DHCP. The problem occurs with both wired and wireless connections. The same routers will allow connections from Windows PCs while failing with Macs. The solution seems to be to go back to the previous firmware version, 1.00.9 for WRT54G available here: ftp://ftp.linksys.com/pub/network/ Look for wrt54gv5_v6_fw_1.00.9_US_code.zip close to the bottom of the list. or 1.50.8 for wrt54gs available here: http://www.sendspace.com/file/fh6st1 The problem may not appear for several days after updating the firmware, but then cannot be overcome by resetting the router or reflashing the new firmware. Flashing the older firmware will restore router function. The problem does not seem to affect PCs but does affect some other devices in addition to Macs.