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I was previously running ubuntu 12.04 and upgraded to ubuntu 12.10. Previously on 12.04 when I removed my wired ethernet connection and plugged in my 3G modem I was immediately able to browse the internet. However now on 12.10 I am unable to do so, even though the modem shows that it is connected when I go to Firefox or Chrome it displays an error. In order for my 3G to work I need to restart my machine (without the ethernet cable plugged in) and then plug in the 3G modem. It then works.

Please help or advise what I can do.


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I was (and am) having a similar problem while connecting to the Internet using my MTS MBlaze (India) dongle which is a ZTE device. I am using Kubuntu 12.10.

A while back I was only able to connect to the device from Network Manager applet, but a ping to any address including resulted in "Network is unreachable". I figured out this could primarily be because of my host not being able to connect to MTS gateway.

'ifconfig' shows something similar to the following:

ppp0      Link encap:Point-to-Point Protocol  
          inet addr:  P-t-P:  Mask:

I used the 'route' command to manually add the gateway address (P-t-P in above ifconfig output) as follows:

sudo route add default gw

And voila, I was able to ping again, even to (as dongle devices auto configure DNS servers as well); there is no need to change /etc/resolv.conf at all.

Now I need to figure out how to automate this. Any help most welcome.

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I just installed and had the same issue with MTS MBlaze. I tried to change the IPV4 settings to Automatic PPP and I could connect.

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