alert udp $EXTERNAL_NET any -> $HOME_NET 53 (msg:"GPL DNS named iquery attempt"; content:"|09 80 00 00 00 01 00 00 00 00|"; depth:16; offset:2; reference:bugtraq,134; reference:cve,1999-0009; reference:url,www.rfc-editor.org/rfc/rfc1035.txt; classtype:attempted-recon; sid:2100252; rev:9; metadata:created_at 2010_09_23, cve CVE_1999_0009, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)