Ports And Protocols

Question 2

What is a port in networking?

Answer 2

A port is a virtual endpoint used by devices to distinguish between multiple services or applications running on the same IP address. Ports ensure that data reaches the correct program.

Question 3

What are the port number ranges?

Answer 3

0–1023 (Well-Known Ports): Used for common services like HTTP (80), HTTPS (443), and FTP (21).

1024–49151 (Registered Ports): Assigned to software vendors for specific applications.

49152–65535 (Dynamic or Ephemeral Ports): Used temporarily by client devices for outbound connections.

Question 4

What are ephemeral ports used for?

Answer 4

Ephemeral ports are short-lived ports automatically assigned to client applications when they initiate a connection to a server. They’re essential for managing multiple simultaneous sessions, like browsing multiple websites.

Question 5

What is the difference between TCP and UDP?

Answer 5

TCP (Transmission Control Protocol): Reliable, connection-oriented protocol that ensures all data is received in order and without error. Used for services like HTTPS, SSH, and FTP.

UDP (User Datagram Protocol): Faster, connectionless protocol that doesn’t guarantee delivery. Used for applications where speed matters more than reliability, such as DNS queries, VoIP, and video streaming.

Question 6

What port does HTTPS use?

Answer 6

443 (TCP) – HTTPS (Hypertext Transfer Protocol Secure) uses TLS/SSL to encrypt web traffic between a browser and a web server.

Question 7

What port does HTTP use?

Answer 7

80 (TCP) – HTTP (Hypertext Transfer Protocol) is used for unencrypted web traffic and is the foundation of data communication on the web.

Question 8

What port does SSL VPN (OpenVPN) use?

Answer 8

1194 (UDP) – OpenVPN uses SSL/TLS encryption to provide secure remote access via a VPN tunnel over the internet.

Question 9

What port does SFTP use?

Answer 9

22 (TCP) – SFTP (Secure File Transfer Protocol) uses SSH (Secure Shell) to securely transfer files over a network.

Question 10

What port does FTPS use?

Answer 10

990 (TCP) – FTPS (File Transfer Protocol Secure) adds SSL/TLS encryption to traditional FTP for secure file transfers.

Question 11

What port does SSH use?

Answer 11

22 (TCP) – SSH (Secure Shell) provides encrypted remote login and command-line access.

Question 12

What port does Telnet use?

Answer 12

23 (TCP) – Telnet allows remote command-line access but lacks encryption, making it insecure for sensitive data.

Question 13

What ports does FTP use?

Answer 13

21 (TCP) for control commands and 20 (TCP) for data transfer – FTP (File Transfer Protocol) is used to transfer files over a network without encryption.

Question 14

What port does TFTP use?

Answer 14

69 (UDP) – TFTP (Trivial File Transfer Protocol) is a lightweight protocol used for simple, unauthenticated file transfers.

Question 15

What port does SMB use?

Answer 15

445 (TCP) – SMB (Server Message Block) is used primarily for Windows file and printer sharing.

Question 16

What port does AFP use?

Answer 16

548 (TCP) – AFP (Apple Filing Protocol) enables file sharing between macOS systems over a network.

Question 17

What port does NFS use?

Answer 17

2049 (TCP) – NFS (Network File System) allows file sharing over a network, mainly used in Unix/Linux environments.

Question 18

What ports does SMTP use?

Answer 18

25 (TCP) for basic mail sending, 587 (TCP) for mail submission with STARTTLS – SMTP (Simple Mail Transfer Protocol) is used to send emails.

Question 19

What port does POP3 use?

Answer 19

110 (TCP) – POP3 (Post Office Protocol version 3) is used to retrieve and download emails from a mail server.

Question 20

What port does POP3S use?

Answer 20

995 (TCP) – POP3S is the secure version of POP3 using SSL/TLS encryption.

Question 21

What port does IMAP use?

Answer 21

143 (TCP) – IMAP (Internet Message Access Protocol) enables users to access and manage email messages on the mail server.

Question 22

What port does IMAPS use?

Answer 22

993 (TCP) – IMAPS is the secure version of IMAP using SSL/TLS encryption for email access.

Question 23

What port does DNS use?

Answer 23

53 (UDP for queries, TCP for zone transfers) – DNS (Domain Name System) resolves domain names to IP addresses.

Question 24

What port does RDP use?

Answer 24

3389 (TCP/UDP) – RDP (Remote Desktop Protocol) allows remote graphical access to Windows machines.

Question 25

What ports does SNMP use?

Answer 25

161 (UDP) for polling, 162 (UDP) for traps – SNMP (Simple Network Management Protocol) is used to monitor and manage network devices.

Question 26

What ports does NetBIOS use?

Answer 26

137-139 (TCP/UDP) – NetBIOS (Network Basic Input/Output System) supports file and printer sharing on legacy Windows networks.

Question 27

What ports does SIP use?

Answer 27

5060 (UDP/TCP) for unencrypted, 5061 (TCP) for secure – SIP (Session Initiation Protocol) is used for initiating VoIP and multimedia sessions.

Question 28

What port does L2TP use?

Answer 28

1701 (UDP) – L2TP (Layer 2 Tunneling Protocol) is used with IPsec for secure VPN connections.

Question 29

What port does PPTP use?

Answer 29

1723 (TCP) – PPTP (Point-to-Point Tunneling Protocol) is an older VPN protocol with known vulnerabilities.

Question 30

What port does IKEv2 use?

Answer 30

500 (UDP) – IKEv2 (Internet Key Exchange version 2) is used with IPsec to establish secure VPN tunnels.

Question 31

What ports does DHCP use?

Answer 31

Ports 67 (server) & 68 (client) – DHCP (Dynamic Host Configuration Protocol) automatically assigns IP configurations like IP address, subnet mask, and gateway.

Question 32

What port does NTP use?

Answer 32

Port 123 (UDP) – NTP (Network Time Protocol) synchronizes clocks across devices, critical for logs, security, and scheduling.

Question 33

What port does SMTPS use?

Answer 33

Port 587 (TCP) – SMTP Secure with STARTTLS adds encryption to email submissions (TLS).

Question 34

What port does LDAPS use?

Answer 34

Port 636 (TCP) – LDAPS (Lightweight Directory Access Protocol Secure) encrypts directory queries with SSL/TLS.

Question 35

What port does Syslog use?

Answer 35

Port 514 (UDP) – Syslog standard in-band messaging for logging events from network devices to centralized servers.

Question 36

What port does SQL Server use?

Answer 36

Port 1433 (TCP) – MS-SQL server communication, used for structured database queries.

Question 37

What port does MySQL use?

Answer 37

Port 3306 (TCP) – Default port for MySQL database connections.