Don't use the latest Ibex Alpha 6 if you run an Intel Gigabit ethernet card, there is a bug
) currently that will screw with the firmware render it inoperable by making the checksum fail. This applies to the e1000e driver but can cause issues if you have used e1000 in the past. The image download page says:
Due to an unresolved bug in the Linux kernel included in these images, they should not be used on Intel ethernet hardware supported by the e1000e driver (Intel GigE). Doing so may render your network hardware permanently inoperable.
Older Intel ethernet hardware which uses the e1000 driver is not affected by this; however, some hardware which used the e1000 driver in previous Ubuntu releases, such as hardware that uses a PCI Express bus, has been moved from e1000 to e1000e in the latest kernel releases. If in doubt, do not use these images, and subscribe to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/263555 to be notified when the bug is fixed.
Yikes! Hope they have it fixed by the 10th.
Update: More info can be found in a discussion on the kernel mailing list.
Update #2: Looks like the main bug report is here. Looks like they are getting close to a resolution.
Update #3: Seems that a fix as been released and the final release of Ibex (8.10) will be out Oct 30th.