alert dns $HOME_NET any -> any any (msg:"ET DYN_DNS DNS Query to DynDNS Domain *.ddns .net"; dns.query; content:".ddns.net"; nocase; isdataat:!1,relative; reference:url,www.noip.com/support/faq/free-dynamic-dns-domains/; classtype:bad-unknown; sid:2028675; rev:3; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2019_10_12, deployment Perimeter, former_category POLICY, performance_impact Low, confidence High, signature_severity Informational, updated_at 2024_06_11;)