Can't use 3G while connected to the LAN

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robhob

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Good day all

I've got a silly problem. My work laptop is a HP ProBook 4520s running Windows 7 Pro. These units come with a built-in 3G modem. If I fire up the modem I can't use it to go online while I'm plugged into the network. I have to either unplug the machine from the network or remove the default gateway address. This is very frustrating... any body got any idea of how to work around it?

Many thanks

robhob
Click here to buy books at a fraction of the SA price from the UK with free shipping.
 
Hey robhob,

This has most likely to do with your Windows' routing table.

Download my Traffic Splitter application, select the 3G connection as the International/Default interface and then click Setup Routes.
If it doesn't work after you've done that, then it has to be something else.
 
robhob:
I'm suspecting that it can be a DNS server problem.

Open Command Prompt and run the following 3 commands:
nslookup www.aardvark.co.za
nslookup www.aardvark.co.za 8.8.8.8
ping 196.25.211.106

Post the results here. You can right-click the window, mark the contents and copy & paste it.
 
Here's the results with the network cable plugged in as well as the 3G running.
C:\>nslookup www.aardvark.co.za
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: 196.207.40.167

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out


C:\>nslookup www.aardvark.co.za 8.8.8.8
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: 8.8.8.8

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out


C:\>ping 196.25.211.106

Pinging 196.25.211.106 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 196.25.211.106:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\>


Thanks for your time.

robhob
Click here to buy books at a fraction of the SA price from the UK with free shipping.
 
robhob:
It seems like your DNS server settings are fine, but your routing table is definitely the issue here.

Could you perhaps run the the following commands in Command Prompt, while the LAN & 3G are connected:
Code: 
ipconfig /all > c:\with-lan.txt
route print >> c:\with-lan.txt
ping 196.25.211.106 >> c:\with-lan.txt

Then disconnect your LAN, while 3G is still connected and then run the following commands in Command Prompt too:
Code: 
ipconfig /all > c:\without-lan.txt
route print >> c:\without-lan.txt
ping 196.25.211.106 >> c:\without-lan.txt

Then send me both the c:\with-lan.txt and c:\without-lan.txt files, either as a PM or to my E-mail address I've sent to you.
 
Here's the solution Pada emailed me:

It seems like it is a routing issue like I've suspected at first.
Using my Traffic Splitter application should solve your problem.

The problem is as follow:
When you have both your 3G & LAN adapters connected, the LAN device takes priority (becomes the default network device). So if you haven't told the PC to route a specific network subnet via the 3G device, the PC would route the traffic via your LAN device.

1) If you've selected the 3G device as the International/Default interface in my Traffic Splitter application and clicked on Setup Routes, then your 3G device should become the new default connection.

2) Alternatively, you could just run the following command to remove the LAN device from being the default:
route delete 0.0.0.0 mask 0.0.0.0 130.10.0.254

3) The last (and probably the best + only permanent) solution would be to go into the LAN adapter's TCP IPv4's Advanced properties and to change it from Automatic Metric to like 9999 (or as big as you can). A bigger number implies a lower priority.

The quickest solution would be #2, but I would suggest that you go with #3 if you want a permanent solution.

Thanks Pada, number 3 did the trick.

robhob
Click here to buy books at a fraction of the SA price from the UK with free shipping.
 
Option 3 works ok

robhob said:
Here's the solution Pada emailed me:

It seems like it is a routing issue like I've suspected at first.
Using my Traffic Splitter application should solve your problem.

The problem is as follow:
When you have both your 3G & LAN adapters connected, the LAN device takes priority (becomes the default network device). So if you haven't told the PC to route a specific network subnet via the 3G device, the PC would route the traffic via your LAN device.

1) If you've selected the 3G device as the International/Default interface in my Traffic Splitter application and clicked on Setup Routes, then your 3G device should become the new default connection.

2) Alternatively, you could just run the following command to remove the LAN device from being the default:
route delete 0.0.0.0 mask 0.0.0.0 130.10.0.254

3) The last (and probably the best + only permanent) solution would be to go into the LAN adapter's TCP IPv4's Advanced properties and to change it from Automatic Metric to like 9999 (or as big as you can). A bigger number implies a lower priority.

The quickest solution would be #2, but I would suggest that you go with #3 if you want a permanent solution.

Thanks Pada, number 3 did the trick.

robhob
Click here to buy books at a fraction of the SA price from the UK with free shipping.
Click to expand...

Yes I agree option 3 seems to be the best. If you are not using ipv6 you need to disable this protocol as well as it also has a metric. The issue of the metric for 3g nic seems to occur in 64 bit. My laptop is 32 bit w7 and strangely this problem does not occur. However, in 64 bit ulitimate, this definately was an issue and appears to be resolved by following option 3. Thanks for the info.

:)
 
Hi, I have tried solution #3 above, however now i cannot access my network. Please kindly advise.
 
Using 3G while connected to your work network probably violates your company's security policies.
 
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