WMP54G + WRE54G Extender + WRT54GC = "Duplicate IP Addresses found"

Question

Hello,
I have a client with a large office and, after measuring signal strength loss in the remote regions of this non-cat5 wired workspace, the best solution for keeping optimal signal strength and speeds on his wireless LAN was to install a Linksys WRE54G Extender/Repeater.  The wireless solution in this place is all LinkSys with latest firmware and drivers.  Here's the layout:
2 Desktop WinXP SP2 computers with LinkSys WMP54G PCI wireless NICs (Installed LinkSys Wireless Managers on both computers);
1 LinkSys WRE54G upstairs (No encryption, Auto configured correctly, 2 solid blue lights, can access the LAN and WAN);
1 LinkSys WRT54GC Wireless Router downstairs (No encryption, MAC Filtering Enabled for the 2 LinkSys Wireless NICs and the LinkSys Extender);
When I press the autoconfig button on the extender, it properly configures itself from the router's information and I get 2 blue lights; The Extender contains the same SSID as the router, which is good.  The Extender is assigned 192.168.1.240; There is no encryption at this time because I want to debug a simple solution, but MAC filtering is enabled on the router to eliminate outsiders from accessing the router/LAN.  When I boot one of the desktop computers, it gets a solid signal and speed, but I get "Duplicate IP Address found" error messages from WinXP.  The IP Addresses are being DHCPed from the router and are not duplicated on this simple LAN.  When I statically assign IP Addresses that are out of DHCP's range, I get the same results; When I use WinXP Wireless Manager, I get the same results; When I use LinkSys' Wireless Manager, I get the same results; When I unplug the Extender, the LAN works properly and I do not get the erorr message, so the issue is definitely something to do with the Extender.  I've searched LinkSys' website for a solution, no go...  I've scoured the Internet, no go... Help!  The only thing that I can think of is that since the router and extender have the same SSID, when the desktop computer's send a request for an IP Address, the router responds and, dutifully, the Extender duplicates the response, which generates the error.  If this is so, how the heck is the Extender supposed to be configured?  Help!  I'd appreciate any suggestions or ideas!  There are many, many postings on the Internet about this problem, but I have not found any solutions.  If I cannot resolve this issue for my client by next Friday, I will have to rip out the LinkSys solution and install another vendor's products.
Thanks,
Mike

Answer 1

I have the same issue. I have discovered something I don't see in this forum thus far. The WRE54G is not allowing the individual MAC addresses of the wireless client PCs to pass through. When I do a network scan from the server, it shows 4 IP addresses as having the same MAC address. Both WRE54Gs, as well as both PCs. I think this is what is causing the duplicate IP issue. How to fix though, I am still working on. Maybe this will help someone else and they can in turn help me.
Setup: Windows 2003 Std Server issuing DHCP. WAP54G providing wireless, 2 WRE54Gs in chain providing wireless access to a warehouse. 2 Windows XP SP2 workstations using Linksys USB wireless adapters.
MTK
Network Engineer
Cayman Technologies, Inc.