I need help.

I have a friend with a small office setup. Several computers, printers, and other devices are networked together through a typical Belkin Wifi/VOIP/4LANport router. The small office network has no internet connectivity.

He has a notebook [Win 7 Home Premium 32-bit] with a builtin WiFi connection. It can access the small office network and attached devices by connecting with the Belkin router via WiFi.

The notebook also has a USB Mobile Broadband stick which allows the notebook to access the internet via the 3G mobile/cellphone network.

When the USB Mobile Broadband is ON and WiFi is OFF, web browsing and email access [Outlook] works. The small office network is not connected, so no printing is possible.

When the USB Mobile Broadband is OFF and WiFi is ON, web browsing and email do not work. Printing etc. is possible.

So far, that's all normal and expected. Where it gets weird is when both the USB Mobile Broadband and the WiFi are activated. The WiFi connection to the small office network seems to take precedence, so the printing etc. still works. However the internet and email stop working altogether. The USB Mobile Broadband is still connected to the cell phone network, but the notebook doesn't sent anything over that connection.

I'd like for all of the notebook's office network data to go over WiFi and its general internet communications to go over the Cell network. How do I get that to happen?

The office network devices are all 10.1.1.x. Should I be investigating ways to route all of the notebook's 10.1.1.x data to the WiFi and everything else to the Cell network, or is there a different way that this should be done?

 

This can work without tweaking, but I've had better results when the PC was a computer on one domain or the other. That said, the network access does follow a precedence. In Windows XP this was found by bringing up the Network Connections, selecting Advanced Settings from the Advanced menu. I recall they buried it further in Windows 7.

Even so, I'd probably leave the WiFi as the first network as shares and printers are more likely defined by IP than by DNS. The problem is the IP range set by the WiFi- 10.x.x.x is a Class A, and thus encompasses a much wider broadcast for addresses to poll before reverting to the secondary network. (I realize that subnetting should allow for a much tighter broadcast, but sometimes a network device just doesn't act as smart as you expect it to).

The solution here would be to change the IP range for the local WiFi to something more like 192.168.200.x which is a Class-C network; the '200' isn't specific, but so many local hubs use 192.168.1.x that I recommend using a different number in the third octet to avoid conflicts when traveling.

There may also be a DNS service running on the WiFi- if that hub isn't providing internet access or named connections to the local server or printer, you should be able to disable the service entirely, which would speed up the switch-over to the secondary USB connection for browsing.

Hopefully this made sense.

 

I think so.

So you're suggesting that I should leave the network precedence alone, and just change the office network over to 192.168.200.x? I should also disable any DNS services running on the router [you're right, everything on that network is defined by IP; DNS isn't required].

If I understand you correctly, then that would be enough for web browsing and the wifi to work together?

So, when the notebook tries to retrieve data from 75.126.162.55 [darklordpotter.net], for example, would it go to the wifi router first, get an error message, then attempt to use the 3G connection? I'm not sure how simply changing the IP range of the home network gets everything working.

My network-fu is weak though, so I'll give this a go tonight.

 

Err, I thought nowadays it was mostly classless inter-domain routing with subnets being defined as ip/subnetbits. If I remember correctly from my networking class. It shouldn't matter what ip you change it to (i.e. you can keep the ips the same in your local wifi network) as long as you change the subnet to something like 255.255.255.0 which would mimic an old school Class C network and is what wordhammer is saying.

I'm not saying that's the solution to your problem. Just another (the correct?) way to achieve what wordhammer is saying. I'm not sure if matching subnets bits on both networks will fix your problem.

Edit: I'll get back to you later on ways to fix your problem, that requires me to lookup some stuff on the internet which I'll do tomorrow.