Snort Message - WARNING: No preprocessors configured for policy 0

Question

I have installed and configured snort 2.9.7.2 and it is running without a problem. However, my question is: what does the following warning mean?

"No preprocessors configured for policy 0"

This message shows when I run the command:

snort -v

Answer 1

I had the same error:

No preprocessors configured for policy 0

That was because I forgot to unpack all the rules into the proper folders. After unpacking the rules, the error went away.

Answer 2

This message indicates that no snort preprocessor is loaded. In order to get rid of this warning, please use the following command:

snort -v -c /etc/snort/snort.conf

Please make sure that the configuration file /etc/snort/snort.conf is present and preprocessors are enabled in the configuration file.