Ports And Protocols

Question 1

What is a port in networking?

Answer 1

A port is a logical “doorway” for communication on a device.

Question 2

What is an example of a port used for secure web traffic?

Answer 2

Port 443, used for HTTPS.

Question 3

What is a protocol?

Answer 3

A protocol is a set of rules for communication between devices.

Question 4

Name three common network protocols and their purposes.

Answer 4

• TCP (reliable transmission)
• UDP (fast, unreliable transmission)
• ICMP (diagnostics)

Question 5

What are Well-Known Ports and their range?

Answer 5

Ports 0–1023, reserved for core services like HTTP, HTTPS, FTP.

Question 6

What are Registered Ports and their range?

Answer 6

Ports 1024–49151, assigned to specific applications like SQL Server.

Question 7

What are Dynamic/Ephemeral Ports and their range?

Answer 7

Ports 49152–65535, used temporarily by clients during communication.

Question 8

What port does HTTP use and what is it for?

Answer 8

Port 80, for unsecured web browsing.

Question 9

What port does HTTPS use and what is it for?

Answer 9

Port 443, for secure web browsing via SSL/TLS.

Question 10

What ports does SMTP use?

Answer 10

Port 25 (insecure), 587 (secure).

Question 11

What is the purpose of SMTP?

Answer 11

To send email.

Question 12

What ports does POP3 use?

Answer 12

Port 110 (insecure), 995 (secure).

Question 13

What is the purpose of POP3?

Answer 13

To download email from a server.

Question 14

What ports does IMAP use?

Answer 14

Port 143 (insecure), 993 (secure).

Question 15

What is the purpose of IMAP?

Answer 15

To sync email across multiple devices.

Question 16

What ports does FTP use, and is it secure?

Answer 16

Ports 20 and 21; it is not secure.

Question 17

What port does SFTP use and what makes it secure?

Answer 17

Port 22; it’s based on SSH.

Question 18

What port does TFTP use and what is its security level?

Answer 18

Port 69; it is not secure and offers simple, no-auth transfers.

Question 19

What port does SMB use and what is it used for?

Answer 19

Port 445; used for Windows file sharing over LAN.

Question 20

What port does SSH use and is it secure?

Answer 20

Port 22; yes, it’s encrypted.

Question 21

What port does Telnet use and is it secure?

Answer 21

Port 23; no, it’s insecure and used mainly for legacy systems.

Question 22

What port does RDP use and what is it for?

Answer 22

Port 3389; used for remote Windows access with encryption.

Question 23

What port does DNS use and what is its purpose?

Answer 23

Port 53 (TCP/UDP); resolves domain names to IP addresses.

Question 24

What ports does DHCP use?

Answer 24

Port 67 (server), 68 (client).

Question 25

What port does Microsoft SQL use?

Answer 25

Port 1433.

Question 26

What port does MySQL use?

Answer 26

Port 3306.

Question 27

What ports does SNMP use?

Answer 27

Port 161 for polling, 162 for traps.

Question 28

What port does Syslog use and why?

Answer 28

Port 514 (UDP/TCP); for centralized event logging.

Question 29

What port does NTP use and what's its function?

Answer 29

Port 123 (UDP); for time synchronization across devices.

Question 30

What ports does SIP use?

Answer 30

Port 5060 (unencrypted), 5061 (TLS encrypted).

Question 31

What ports does LDAP use and what is it for?

Answer 31

Port 389 for regular access, 636 for secure (LDAPS).

Question 32

How does TCP differ from UDP in terms of connection type?

Answer 32

TCP is connection-oriented; UDP is connectionless.

Question 33

Which protocol is more reliable: TCP or UDP?

Answer 33

TCP, due to acknowledgments and retransmissions.

Question 34

Which protocol has lower overhead?

Answer 34

UDP.

Question 35

Give examples of use cases for TCP.

Answer 35

* Web browsing * Email * File transfers

Question 36

Give examples of use cases for UDP.

Answer 36

* Streaming * VoIP * Online gaming

Question 37

What is ICMP used for?

Answer 37

Diagnostics such as ping, traceroute, and error reporting.

Question 38

At which OSI layer does ICMP operate?

Answer 38

Layer 3 (Network layer).

Question 39

Name two common ICMP-based attacks.

Answer 39

* ICMP Flood * Ping of Death

Question 40

Why might admins block ICMP traffic?

Answer 40

For security, although it limits diagnostic capabilities.