Problem using mobile broadband and wired network at the same time

Asked by Shogun

Dear all,

maybe someone can assist a beginner to solve a problem. I have set up mobile broadband and wired network in the network manager in Ubuntu 11.04. Yet, they won't work at the same time. Wired network seems to have priority and is connected at start up. To get the mobile broadband connection running I have to manually delete the wired network from nm every time. The other way around I can get the wired network running by disabling mobile broadband. I tried to fix things by manually configuring the wired network, but it didn't help.

NM in Ubuntu seems to see these two connections as two different networks and doesn't accept them running at the same time. In Windows 7 as well as in XP the same combination works without any problems.

Any idea how to fix this problem? Maybe by handling mobile broadband through wvdial and wired network through NM? This may be a workaround, but I'd prefer to handle both connections through NM.

Any help is very appreciated.

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Ubuntu network-manager Edit question
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Duncan Thomas (luciomrx) said :

There are hard way to do it but here's simple one.
Try to install wicd. it is another network manager that allows you to connect them at the same time.
terminal > sudo apt-get install wicd-gtk
for your wired should be fill with eth0
for your wireless should be wlan0
I guess why NM in Ubuntu doesn't allow to connect the same time, it is probable security reasons.

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Shogun (nenadov-nenad) said :

Unfortunately this didn't work out. Wicd won't recognize my cdma modem.

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Mathieu Trudel-Lapierre (cyphermox) said :

Shogun, indeed, wicd isn't exactly meant for that.

You can definitely have both wired and broadband run at the same time in NM, however there is a definite gotcha: wired, if left configured as it is by default, will always take priority (this is meant to avoid having you get charges for broadband when you could connect to the internet via wired). The workaround to this is to either:

1) disconnect wired (there should be a "Disconnect" entry in the NM menu at the top of your screen). No need to delete it ;)
2) Create another connection for Wired, (Edit Connections -> Wired tab -> Add; then set it to "Only use for the resources on its network", under the IPv4 tab, in the dialog that comes up when you click the Routes button). Then, use the default standard one ("Auth eth0" or whatever) for a normal connection to the internet over wired, and the new connection you created when you want to connect to your local network over wired but access the internet over mobile broadband. Again, you'll be able to switch between the two in the NM menu at the top of your screen.

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sdaau (sd-imi) said :

Just wanted to say thanks and +1 to @mathieu-tl for the alternate "Only use for the resources on its network" entry - works great for me - cheers!

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