I've run an Ethernet cable to a second floor bedroom router (TP-LINK TL-WR841ND) to give better network connectivity due to distance from the first floor access point, which is also a TL-WR841ND. This cable is connected from yellow LAN port on the secondary to yellow LAN port on the primary. There is no cable plugged into the blue WAN port on the second floor router. Followed DD-WRT tutorials for setting the second router up to create a single network in the house (same SSID/security, IP subnet same, DHCP disabled, etc.) The WiFi and hardwired connections are solid - greatly increasing upload and download speeds in the second floor bedroom. Here is where the problem comes in - when a Windows PC (either Win7 or Win10) connects to the secondary router, the rest of the home network is no longer available to that PC. This occurs when the PC is connected either wirelessly or hardwired to the second upstairs router. Forcing a connection (via Virtual Wireless Interface) to the main router (the downstairs one connected to the WAN) restores access on the PC to the home network. Is there a setting on either router that needs to be changed to allow access to the home network, which is a Windows Workgroup? Do you have any suggestions, outside of router settings, about how to fix this problem?