Member Avatar for ruzicka38

xp pro on PC
linksys wrt54gs wireless router
cnet pro200wl pci fast ethernet adapter
Wireless connection between the rest of the PCs/laptops in the house works perfectly. Just recently, the wired connection with configuration listed above, has failed to work. If connected to the modem directly internet access is available. Through the router it does not work. Linksys insists, after 40 minutes of troubleshooting, that the problem is with the PC not the router. It appears the network card is the issue, but only when used through the router. Any ideas? I'm lost.

alan

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— building on 's MAC-filter suggestion, the symptom (works on the modem but not through the router) is most often a router-side access control, DHCP issue, or a link/driver mismatch rather than a general ISP problem. The following concise troubleshooting sequence covers the common causes and fixes that were not detailed in the thread.

  • Check the physical layer first: confirm the NIC and router port show link/activity lights, swap the Ethernet cable, and try a different LAN port (or plug the desktop into the same port a working wired machine uses).
  • Verify IP/DHCP on the desktop: run ipconfig /all. If the address is in the 169.254.x.x range, DHCP is failing. Copy the Ethernet adapter "Physical Address" (MAC) from that output.
  • If the desktop cannot reach the router admin, use another wired PC to log into the router and either add the desktop MAC to the allow list or temporarily disable MAC/address-based filtering. If needed, set a temporary static IP on a wired machine in the router's LAN subnet (for example, if the router is 192.168.1.1, use 192.168.1.50/255.255.255.0 gateway 192.168.1.1) to access the admin UI.
  • Check the router UI for all access controls (some firmware separates wireless MAC filters from broader access restrictions). Also inspect the DHCP lease table for the desktop's MAC.
  • Rule out OS/firewall and driver problems: briefly disable Windows/third-party firewall, boot with Networking in Safe Mode, reinstall/update the NIC driver, and try forcing 100Mbps/full-duplex if auto-negotiation looks unstable.
  • Test hardware: try a different NIC (USB or spare PCI), or plug the desktop NIC into another known-good switch to confirm the card itself.

Note: back up router settings before a factory reset; reset only as a last resort. If all config and hardware checks pass but the problem persists, replacing the NIC is a low-cost next step.

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Member Avatar for Member #119018

Do you use MAC Address filtering on the router?

Member Avatar for ruzicka38

Do you use MAC Address filtering on the router?

That is one of the things linksys had me do. I had to use a wired laptop to access the router settings. I could not access the router at all from the recently affected PC.

Member Avatar for Member #119018

You must add your desktop PC's Ethernet adapter into the MAC address list or the router will block all communications coming from that MAC address.

Member Avatar for ruzicka38

You must add your desktop PC's Ethernet adapter into the MAC address list or the router will block all communications coming from that MAC address.

How do I do that not being able to connect to the router from that PC?

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