TCP & UDP Questions

Question 1

FTP purpose and port number

Answer 1

• File Transfer Protocol
• Transfers files between systems
• Authenticates with a username and password
• TCP/20
• TCP/21

Question 2

DNS purpose and port number

Answer 2

• Domain Name System
• Turns names into IP Addresses
• UDP/53

Question 3

HTTPS purpose and port number

Answer 3

• Hypertext Transfer Protocol Secure
• Web server communication with encryption
• TCP/443

Question 4

NetBIOS/NetBT purpose and port number

Answer 4

• Allows computers and applications to communicate with network hardware, and allows data to transmit properly over a network.
• UDP/137/138/139

Question 5

HTTP purpose and port number

Answer 5

• Web server communication

- TCP/80

Question 6

SLP purpose and port number

Answer 6

• View list of available servers
• TCP/427
• UDP/427

Question 7

SSH purpose and port number

Answer 7

• A secure protocol for remote logins
• A user can connect to a server to transfer information
• TCP/22

Question 8

POP3 purpose and port number

Answer 8

• Used to receive mail

- TCP/110

Question 9

Telnet purpose and port number

Answer 9

• Login to devices remotely
• Not encrypted
• TCP/23

Question 10

SMB/CIFS purpose and port number

Answer 10

• File sharing between computer using it
• Commonly used by Microsoft computers
• TCP/445

Question 11

AFP purpose and port number

Answer 11

• File sharing between computer using it
• Used by Apple computers
• TCP/548

Question 12

SMTP purpose and port number

Answer 12

• Used to send mail

- TCP/25

Question 13

DHCP purpose and port number

Answer 13

• Auto config of IP address, subnet mask and other options

- UDP/67/68

Question 14

RDP purpose and port number

Answer 14

• Share a desktop from a remote location

- TCP/3389

Question 15

LDAP purpose and port number

Answer 15

• Store and retrieve information in a network directory

- TCP/389

Question 16

SNMP purpose and port number

Answer 16

• Used to manage devices on a network

- UDP/161/162

Question 17

Difference between TCP and UDP?

Answer 17

TCP - Transmission Control Protocol (

		- Reliable delivery, there are possesses to make sure things go through the network with little problems.
		- "Flow Control" When data is received, the sender is notified so the amount of data sent is managed. If data isnt received the sender is notified and it resends.

UDP - User Datagram Protocol (Connectionless, this means no “call” is made. Data is sent with no hellos or goodbyes)

		- Unreliable delivery meaning no error recovery and no acknowledgement is sent back from the receiver.
		- No "Flow Control" The sender determines the amount of data transmitted.