Split from bug 166804. Secon on one of my students ("martindr2"), when he initially graded his lab test, it said that eth0:151 was not found in the network configuration, but it was clearly there, and subsiquent grading attempts repeated found it. I cleared the score and had him regrade the test, but thought you should know about this potential bug. I looked through the .bash_history and such and could find no evidence that he attempted to correct a misconfiguration after the fact before reporting the error to me, so I believe that the grading was truely in error. If you need any info from the server for this, please let me know.
Currently not enough info to debug, and not heard of similar symptoms, but will leave bug entered to track the potential problem.