CCIE Security FAQ Application Protocols Q1. RFC 1700 defines what well-known ports for DNS? a. TCP port 21 b. TCP port 23 c. UDP port 21 d. UDP port 53 e. TCP/UDP port 53 Answer: e Explanation: DNS is permitted by RFC 1700 to use both TCP/UDP port 53. Typically UDP is vendor configured for UDP port 53. Q2. What supplies DNS security? a. A default username/password … [Read more...]