I recently installed a new router to an existing network at a local office where I do computer work. This was done mainly to extend the wi-fi to two outdoor trailers (the building's aluminum walls knock down the "main" office's existing wi-fi signal). They already had a range extender in place for the first trailer, but needed the wi-fi to reach the second trailer. However the issue that occurred involved only the LAN connections on each PC, with the wireless connections disabled on all PCs with wireless NIC cards.
Here's the setup:
1. A modem somewhere outdoors, on a tower (it's that kind of ISP). Make and model unknown. I didn't bother climbing the tower to check. From there, a CAT-5 cable goes to...
2. The WAN port in Router 1 (the original router), which is a Netgear WNDR3300. IP address: 192.168.1.1. DHCP enabled and set to assign address range 192.168.1.100 - 192.168.1.199. Connected to port 1 is a CAT-5 cable that goes to a 24-port Netgear switch. All of the office PC's are connected to this and configured to "Obtain IP address and DNS server automatically". Connected to port 2 is a CAT-5 cable that goes to...
3. Port 1 (not the WAN) in Router 2 (the new router), which is a Belkin F9K1002. IP address: 192.168.1.2. DHCP disabled. Connected to port 2 is a CAT-5 cable that goes to...
4. A wi-fi range extender, which is a Linksys WRE54G. IP address: 192.168.1.3.
This setup worked all day on Friday, but Monday morning I received a call from the Office Manager regarding connection issues (involving hard-wired PCs) and some error messages. I went in to investigate and found that nearly every computer was throwing "IP address conflict" errors. My first thought was that maybe, somehow DHCP got enabled on Router 2. This was not the case, DHCP was still disabled. Disconnecting Router 2 from the network instantly solved the "IP address conflict" issue, and reconnecting it instantly caused the issue to start again.
I cannot, for the life of me, figure out what is wrong with the setup that is making that happen. If I left out any necessary information, please do not hesitate to ask.
EDIT: Almost forgot, I also tried connecting Router 2 to an open port on the Netgear 24-port switch, instead of directly to Router 1, but the issue persisted.
Edited by pezmutwal, 01 July 2013 - 08:26 PM.