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I have been stuck on this issue for two days now and couldnt find a fix for this. I installed a realtime kernel with

sudo apt-get install linux-rt

because KauNet (which is an ipfw extension) requires a real-time kernel for millisecond granularity.

However after trying to install KauNet I get this error message:

ERROR: Kernel configuration is invalid.
include/linux/autoconf.h or include/config/auto.conf are missing
Run 'make oldconfig && make prepare' on kernel src to fix it.

Both files are there. auto.confcan be found in /usr/src/linux-headers-2.6.31-10-rt/include/config and autoconf.h is in /usr/src/linux-headers-2.6.31-10-rt/include/linux.

Before I installed 2.6.31-10-rt kernel i was on 2.6.32-21-generic and KauNet/ipfw was working.

I appreciate any help. Thanks.

share|improve this question
A little late, but maybe you can reconstruct in case you have solved the issue in the meantime: Is kernel-package installed? –  Karl Richter Dec 25 '14 at 20:04
After all I have solved the issue. I can't recall how I did it though. It was quite a while ago I am afraid. –  derTimo Jan 5 at 17:04

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