alert tcp any any -> any 4660:4799 (msg:"ET P2P ed2k file request answer"; flow:to_server,established; content:"|e3|"; offset:1; content:"|00 00 00 59|"; distance:2; within:4; reference:url,www.giac.org/practical/GCIH/Ian_Gosling_GCIH.pdf; classtype:policy-violation; sid:2000333; rev:11; metadata:created_at 2010_07_30, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)