I have a wireless and wired network in my house. My internet access is via ADSL using an Eircom supplied and branded Zyxel P-660HW-T1 v3 running:

ZyNOS firmware: 3.70(BOE.3)D0|03/30/2010
DSL Firmware:

When I work in my home office I use my laptop to connect to the network using a wired connection (I'm wired for gigabit ethernet, the router hangs off this switch).

My laptop is a Dell Vostro 1720 running Windows 7 Ultimate 64-bit and it has an Intel 5300 AGN wifi interface and a RealTek 8168 PCIe GBE NIC.

Both interfaces have the same static private IP address but only one interface is used at a time.

In the evening I disconnect from the wired network take the laptop into the lounge and connect to my network using wifi. To do this I:

  1. Unplug the ethernet cable
  2. Disable the wired NIC in Control Panel -> Network Connections
  3. Enable the wifi interface.
  4. Connect to the wifi network using the notification area wireless network widget

This all works fine until I try and reconnect to the wired network in the office. When I reconnect to the office wired network I do:

  1. Attach the ethernet cable
  2. Disconnect from the wifi network using the notification area widget
  3. Disable the wifi interface in Control Panel -> Network Connections
  4. Enable the wired NIC

At this point something seems to break:

  • I can ping all the devices on my private LAN just fine, including the the router
  • I can't ping/tracert or connect to any external IP's e.g.

To resolve this I basically have to reboot the router and then all is well until the next day when I go through the same routine again.

When I do a tracert -d the first hop is the router but I get no further than that and the requests time out.

Why would this be happening?

  • if you leave both interfaces enabled they will both be connected to the network and win7 will use the wired lan when plugged in (as wired has higher priority) and will automatically switch to the wireless lan when you disconnect the wire. – Mohamed Nov 10 '10 at 8:14

My first thought on this would be an address resolution protocol issue caused by two interfaces with different MAC addresses having the same IP in rapid succession. It may be that when you connect the cable low-level network functions are being carried out even though your ethernet NIC is disabled (for example, a PXE ethernet adapter might perform DHCP even though it is not enabled in the operating system). Do you get the same result if you disable the wireless adapter, enable the ethernet adapter, and then plug the cable in?

  • Thanks for the reply....I'll give that a go when I get a bit of time later today. – Kev Nov 10 '10 at 10:21
  • I just ended up having two different IP addresses (one for wireless and one for wired). I leave both the Wired and Wireless NIC's enabled and all is good. I decided I can live with that. – Kev Dec 17 '10 at 23:27

when using the Wi-Fi on a laptop there is a FN button when the wi fi wont allow the wired connection to be use you have to press the FN key with the F11 depend on the laptop some are F6 others is just shift and FN key this turns off the wi fi then allows the wired internet Ethernet to switch over from the wi- fi and or Blue tooth connection,

On some laptop you cant run both at the same time on other laptops like my Acer I can have the Wi-Fi turn on and still have the Ethernet connection going with out an issue yet my Dads my HP pavilion you have to either remove the Ethernet cable to use the wi fi side of the laptop or switch off the Wi fi using the FN key to access the Ethernet side of the laptop.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.