The WRT54G is connected to a ZyWall 35 router and is set to router mode with DHCP turned off. The "Internet" port on the LinkSys is connected to an input port on the ZyWall.
When I first tried to set this up, devices connected to the WRT54G could not see the Internet unless the cable to the ZyWall was plugged into an input jack instead of the WRT54G's "Internet" jack. Fiddling with it over a period of days, it finally started working properly with the cable to the ZyWall plugged in to the LinkSys "Internet" jack.
Now, for no apparent reason, it has reverted to the weird mode - devices can't see Internet unless cable to ZyWall is plugged into a Linksys input jack.
The cable to the ZyWall and ZyWall port have tested good (device works when connected via this cable to ZyWall). The cables from devices to the LinkSys are good since those devices see the Internet if a Linksys input port instead of the Internet port is connected to the ZyWall.
I would swear that I had the LAN-WAN wiring working (internet and other computers but visible) with the WRT54G on the same subnet as the ZyWall with the WRT54G in "Router" mode with NAT off. Maybe this is my first true "senior moment."
In any case, just bought a wired switch to replace the WRT54G.
