Moving laptop, no Internet connection

[Hans L]

Hello:

When I have my laptop on the first floor, it connects to my wireless network and the Internet. When I disconnect from the wireless network, turn off the laptop, move it down to the basement, and connect the Ethernet cable (to cable modem/router; it is too far for the wireless network there), the laptop does not connect to the Internet.

If I shut off the modem/router (gateway), and turn it on again, and turn on the laptop, Internet connection is restored.

What could be wrong?

Laptop: Toshiba L675
Gateway (cable modem + router): Motorola SURFboard gateway SBG6580
OS: Windows 7 Home Premium

Thanks,

Hans L

 

[ZyanWu]

I think it might have something to do with the ARP cache.

ARP is a protocol that links an IP address to a MAC address. And if you switch then the MAC address will be on the Ethernet link but the router will still use the WLAN IP. The cache entry might not expire instantaneously, I'm guessing there is a hold timer of some sort.

If you leave it alone, does the laptop get internet access after a period of time? (like 5 mins).

 

[Hans L]

Zyan, thank you for your suggestions. No, no access after even 10 minutes. Can the ARP be reset or erased?

Regards,

Hans L

 

[ZyanWu]

Well, it gets erased every time you restart it but... manually, without restarting, I don't know. I didn't find proper documentation for your router (something where I can see the menus and options).
Also, it might be a routing table problem (same as above, the table's not updating) or even a security feature.

I'd say have someone who knows a thing or two about networking come and take a look in the router's menu. There should be something there.
Or ask someone you trust to connect remotely to your router (there's a link and a checkbox that allows remote access to your router somewhere in the menu.)

I've attached an image of what my routing table + ARP table look like so you know what you're looking for.