alert udp any any -> any 53 (msg:"GPL POLICY MISC Tunneling IP over DNS with NSTX"; byte_test:1,>,32,12; content:"|00 10 00 01|"; offset:12; rawbytes; threshold:type threshold, track by_src, count 50, seconds 60; reference:url,nstx.dereference.de/nstx/; reference:url,slashdot.org/articles/00/09/10/2230242.shtml; classtype:policy-violation; sid:2100208; rev:3; metadata:created_at 2010_09_23, confidence Medium, signature_severity Informational, updated_at 2019_07_26;)