Comment 7 for bug 347718

I am using a Huawei E220 3G modem on the Optus network in Australia.
I recently upgraded to Ubuntu 9.04 and after a couple of weeks I noticed that the mobile broadband was not working. (I only use it occasionally, usually I am on an ADSL connection)

The profile that Network Manager sets up for Optus 3G has these settings in IPv4 tab:
Method: Automatic (PPP) Addresses only
DNS Servers: 202.139.83.3, 192.65.91.129

The DNS IP addresses set by the Network Manager appear to be invalid. They do not respond to ping.

The Optus site lists these correct DNS addresses:
211.29.132.12, 198.142.0.51

Changing Network Manager to these addresses makes the mobile broadband work.

Another way to fix the problem is to change the Method to:
Automatic (PPP)
instead of the default:
Automatic (PPP) addresses only

This disables the DNS address field, and I assume gets the addresses automatically from the ISP.

I booted up from a 8.10 Ubuntu Live CD to check what the settings were. They appear to be the same as in 9.04, so I don't understand why my Optus modem used to work in 8.10.
Perhaps Optus has recently disabled some old DNS servers on one or both of the addresses used by Network Manager.

It may be better if Network Manager defaulted to the Method Automatic (PPP) setting and get the DNS addresses automatically.