Upgrade from Xubuntu 8.04 to 8.10 breaks network management and DHCP

[user1111]

After upgrading Xubuntu from 8.04LTS to 8.10 wired networking is broken. NetworkManager shows a red X on it's icon and left clicking on it shows "Wired Network" followed by "device is unmanaged". The network device is the common on-board Intel Ether Pro 100 and worked without problems before the upgrade. ifconfig shows that eth0 is getting an IP address from DHCP but etc/resolv.conf has only the single line "# Generated by NetworkManager" in it. The local DHCP server is providing correct DNS information to all other clients on the network and so is not likely to be the problem.

At this point I suspect the upgrade process corrupted some configuration settings. However, neither I nor anyone in the forums has been able to identify those settings. My only option now is to reformat and reinstall from scratch. I will try to report back as to whether that fixes it.

[user1111 (user1111)]

OK, I have been shown a work-around/fix on the forums. It seems that the upgrade to 8.10 removed the 'network-administrator' tool from the 8.04 installation and installed a new version of NetworkManager. Perhaps this new NetworkManager is thus intended to replace 'network-administrator'. The problem is that the upgrade process leaves the old settings that 'network-administrator' created in place rather than importing them into the new NetworkManager and the new NetworkManager is incompatible with them, kind of leaving things locked up. The work-around/fix is to manually edit '/etc/network/interfaces' to remove any lines that 'network-administrator' may have created there. After that NetworkManager will manage the interface.

If 'network-administrator' is going to be replaced with NetworkManager, then perhaps the upgrade process needs to be fixed so that it doesn't leave these old configuration settings behind but properly imports them into NetworkManager instead.

[Charlie Kravetz (cjkgeek)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This bug did not have a package associated with it, which is important for ensuring that it gets looked at by the proper developers. You can learn more about finding the right package at https://wiki.ubuntu.com/Bugs/FindRightPackage . I have classified this bug as a bug in network-manager-applet.
For future reference you might be interested to know that a lot of applications have bug reporting functionality built in to them. This can be accessed via the Report a Problem option in the Help menu for the application with which you are having an issue. You can learn more about this feature at https://wiki.ubuntu.com/ReportingBugs.

[Alexander Sack (asac)]

do you have any config for eth0 in /etc/network/interfaces? If so, please remove that content and restart system.

[Victor Vargas (kamus)]

We are closing this bug report because it lacks the information we need to investigate the problem. Please reopen it if you encounter that this issue is still occurring or even better if you can check in latest Ubuntu Karmic version. To reopen the bug report you can click under the Status column, and change the Status back to "New". Thanks again!