In my newly-installed Ubuntu 12.04 LTS, my ZTE K3805-Z Vodafone-branded USB 3G dongle shows in the notification area as a 'Mobile Broadband' connection called 'Vodafone Contract'. So far, so good!
...BUT I cannot access the Internet. I receive the error 'Problem loading page - server not found'. Firefox works with a wired connection and the dongle works under Windows Vista (which I detest!). If someone out there can fix this, I promise to delete Windows Vista!
Open up a terminal from Applications -> Accessories. Type:
sudo gedit /etc/modules
At the bottom of the file, make two new lines, like this:
usbserial
option
Then close the editor program and save it. Reboot the computer and hopefully you’ll be right from now on!
I also had problem with my huaway e173 3g modem. It was restarting and not conecting to the network. However I found a solution. When I was configuring my mobile broadband connection, the system found my usb dongle as "huaway e173", but with this setting was restarting. So I tried selecting "any GSM device" and now my 3g is working. All other setting are default as found by the manager.
Did you enter the username and password when you created the connection? In the option to edit VODAFONE CONNECT you will find a tab called MOBILE BROADBAND where you have to put the username and password.
You can get the details of it by googling for it or from Vodafone Customer Care. Or if that dongle uses an application in windows,in that application too, in settings you will find those details entered.
I had the same issue and here is what worked for me:
Vodafone 3g pen k3805-z requires sudo ifconfig usb0 -arp prior to connecting to achieve connectivity. It appears as if everything is blocked unless arp is disabled.
See this bug report for more clarity: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/764003
