If Ubuntu is connected to more than one network (e.g. GSM and wireless) but only GSM has internet access, OS is unable to access internet. NM version 0.7.
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
network-manager (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
Using NM 0.7 in Hardy (via ppa). I stumbled upon this bug as I am currently without DSL access and have to resort to my GSM connection (through a vodafon modem). The wireless network also allows me to access other computers in the network, so even without internet access it can be useful.
NM is able to handle both connections flawlessly, one at a time. However, if I try to stay connected to both, I am unable to have internet access. Considering that the tray icon status indicates connection to the wireless network, I am inclined to think that NM considers the wireless network more reliable by default and tries to connect to the internet ONLY through it. As this program manages all connections in the OS, this means that every program (including even cli ones such as ping and traceroute) try to reach the net only using the wireless, and local only, network.
As soon as I disable wireless access, I am able to reach the web - even if the modem had been connected to the GSM network all the time.
This could stem from the fact that AFAIK NM is unable to determine if a connection is local only or instead provides internet access.
Desired behaviour: the same I get in Windows Vista. Its connection manager is able to determine whether a connection is local only or provides internet access (maybe pinging some servers or the DNS server?). Moreover, if I connect to two networks at the same time, as in the example above, it can correctly determine which one is functional. Therefore, the user is able to stay connected to more than one network at a time and still have internet access.
I can confirm this behavior on two Intrepid RC machines.
I guess the reason is that the 3g connection doesn't replace the default route upon connection. Adding an option like "Replace default route upon connection" (or preferably "Use this connection to access Internet through while connected") to the network connection options and the configuration guide would solve this issue.
Currently, the only way to gain internet access through a gsm connection in nm is to disconnect from wired and wireless networks and then connect...
(There may be some way to accomplish this by modifying the ipv4 routes settings for the connection, but I wouldnt even dare guess how.)