Examkin

Question

Difficulty: Very hardNetworking Ports and Protocols

A network technician is configuring outbound traffic rules on a perimeter firewall for a dedicated network administration workstation. The workstation must be capable of establishing encrypted command-line remote management sessions with remote Linux servers and performing hostname-to-IP address resolutions against internal DNS servers. Which of the following port and transport protocol combinations must be permitted through the firewall to fulfill these requirements? (Select TWO).

  1. TCP port 22Answer
  2. UDP port 53Answer
  3. C
    TCP port 23
  4. D
    UDP port 67

Answer

The firewall must allow outbound traffic on TCP port 22 for Secure Shell (SSH) remote command-line management and UDP port 53 for Domain Name System (DNS) hostname resolution.
Secure remote command-line administration requires SSH, which uses TCP port 22 to encrypt session data. Hostname-to-IP address resolution relies on DNS, which uses UDP port 53 for standard name lookup requests.

Step-by-Step Solution

1
Identify the protocol and port required for secure command-line administration
SSH provides encrypted shell access and operates over TCP port 22.
Telnet operates on TCP port 23 but sends credentials and commands in plaintext, making it insecure.
2
Identify the protocol and port required for hostname-to-IP resolution
DNS performs hostname resolution and standard client queries use UDP port 53.
DHCP uses UDP ports 67 and 68 for IP address leasing rather than domain name lookups.
3
Select the correct combination matching both requirements
TCP port 22 and UDP port 53 satisfy all stated requirements.
Both selected options correspond to the exact transport protocols and port numbers designated by IANA for SSH and DNS services.

Key Concept

Standard Network Ports and Transport Protocols for SSH and DNS
Estimated Time:2m 0s
Rate this question

Topics

Networking Ports and Protocols

More questions from this topic