[feisty] network-manager overwrites /etc/network/interfaces, doesn't connect

Binary package hint: network-manager

Dell Latitude D620 laptop with up-to-date feisty (as of 2/1/07), an Intel 3945ABG wireless card, and a Broadcom BCM5752 ethernet card. Note that installation was done via dist-upgrade, not fresh CD install. Problem has been occurring for several weeks.

When changing setting on the wireless (i.e. essid), network-manager overwrites /etc/network/interfaces with a file containing only the loopback devices, and then fails to connect (or see the network). Originally, it reported that all interfaces were in "roaming" mode, but that no longer occurs, so the bug seems to be gradually getting better.

Writing the /etc/network/interfaces file manually and using ifdown/ifup to bring up the interface works correctly and connects without a glitch.

I've seen some things suggesting that network-manager is no longer using /etc/network/interfaces, but I don't know where else the information would be stored to troubleshoot.