When probing LDNSs, which protocol is used by default? 07/21/2017 – by Mod_GuideK 0 When probing LDNSs, which protocol is used by default? A. TCP B. ICMP C. DNS_REV D. DNS_DOT SHOW ANSWERSCorrect Answer: B Explanation/Reference: Download Printable PDF. VALID exam to help you PASS.