Ports

Question 1

Which ports are reserved/need admin access?

Answer 1

0-1023

Question 2

What is the difference between UDP and TCP?

Answer 2

UDP: Connectionless model; simple protocol for delivering packets of data. However, packets could be dropped, lost, or arrive out of order. Useful for video call. NTP, DNS, DHCP.

TCP: Connection-oriented protocol that provides a byte stream of data. 3-way handshake and acknowledgment of packets being received. Offers reliable transmission of data. Lost packets can be retransmitted. Used when data must be reliable and in order. Email (SMTP), web (HTTP, HTTPS), File Transfer Services (FTS), Secure Shell (SSH)

Question 3

What port is DHCP on? (Dynamic Host Configuration Protocol)

Answer 3

Port 67

Question 4

What port is DNS on? (Domain Name System)

Answer 4

Port 53

Question 5

What port is NTP on? (Network Time Protocol)

Answer 5

Port 123

Question 6

What port is SMTP on? (Simple Mail Transfer Protocol)

Answer 6

Port 25

Question 7

What port is IMAP on? (Internet Message Access Protocol)

Answer 7

Port 143

Question 8

What port is Telnet on? (Teletype Network)

Answer 8

Port 23

Question 9

What port is SSH on? (Secure Shell)

Answer 9

Port 22

Question 10

What port is FTP on? (File Transfer Protocol)

Answer 10

Port 21

Question 11

What port is SFTP on? (Secure File Transfer Protocol)

Answer 11

Port 22 (Uses SSH as a sub system)

Question 12

What port is HTTP on? (HyperText Transfer Protocol)

Answer 12

Port 80

Question 13

What port is HTTPS on? (Hypertext Transfer Protocol Secure)

Answer 13

Port 443