Originally Posted by ironface007
Need help on snort error message : cannot decode data link type 201
Read the "Question Guidelines" and "How to ask a smart question" links in my posting signature. You provide NO details at all that would let us be able to help you. Things like version of Snort, any relevant config file information, version/distro of Linux, etc. All you've given us is a generic error message, with little context behind it.
Best guess: you haven't specified the correct interface. Correct it in the snort config file.