Securing Server Ports | CompTIA Server+ Exam SK0-004

Which Open Ports to Close for Proper Server Security?

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Question

Which of the following open ports should be closed to secure the server properly? (Choose two.)

A.

21 B.

22 C.

23 D.

53 E.

443 F.

636

CD.

Reference: https://www.csoonline.com/article/3191531/securing-risky-network-ports.html.

Explanations

Which of the following open ports should be closed to secure the server properly? (Choose two.)

A.

21

B.

22

C.

23

D.

53

E.

443

F.

636

CD.

https://www.csoonline.com/article/3191531/securing-risky-network-ports.html

The open ports that should be closed to secure a server depend on the services that are running on it and the security requirements of the organization. However, based on the options given in the question and the security risks associated with the services that use these ports, the two open ports that should be closed are:

A. 21 - This is the port used by the FTP (File Transfer Protocol) service, which allows users to transfer files over a network. FTP is an insecure protocol that sends data in clear text, including usernames and passwords, making it vulnerable to interception and snooping by attackers. Therefore, unless the FTP service is essential for business operations, it is recommended to close this port.

C. 23 - This is the port used by the Telnet service, which provides remote access to a server's command-line interface. Telnet is an insecure protocol that also sends data in clear text, including login credentials, making it easy for attackers to intercept and use this information to gain unauthorized access to the server. Therefore, unless Telnet is necessary for business operations, it is recommended to close this port and use a more secure protocol like SSH (Secure Shell) instead.

B, E, and F are secure ports that should be left open if the services that use them are necessary for business operations. Port 22 is used by SSH, which provides secure remote access to the server's command-line interface. Port 443 is used by HTTPS, the secure version of the HTTP protocol used by web servers to provide encrypted communication between the server and the client's web browser. Port 636 is used by LDAPS (LDAP over SSL/TLS), a secure version of the LDAP (Lightweight Directory Access Protocol) used for directory services.

D is the port used by the DNS (Domain Name System) service, which translates domain names into IP addresses. DNS is an essential service for internet connectivity, and closing this port would disrupt network operations.

In summary, the two open ports that should be closed to secure the server properly are 21 (FTP) and 23 (Telnet).