Common Network Ports

Question 1

TCP 20/21

Answer 1

FTP
File Transfer Protocol
Sends and receives files between systems

Question 2

TCP/22

Answer 2

SSH
Secure Shell
Encrypted console access

Question 3

TCP/23

Answer 3

Telnet
Telecommunication Network
Insecure console access

Question 4

TCP/25

Answer 4

SMTP
Simple Mail Transfer Protocol
Transfer mail between mail servers

Question 5

UDP/53, TCP/53

Answer 5

DNS
Domain Name System
Converts domain names to IP addresses

Question 6

tcp/80

Answer 6

HTTP
Hypertext Transfer Protocol
Web server communication

Question 7

tcp/443

Answer 7

HTTPS
Hypertext Transfer Protocol Secure
Web server communication with encryption

Question 8

tcp/110

Answer 8

POP3
Post Office Protocol version 3
Receive email into an email client

Question 9

tcp/143

Answer 9

IMAP4
Internet Message Access Protocol v4
A newer email client protocol

Question 10

tcp/3389

Answer 10

RDP
Remote Desktop Protocol
Graphical display of remote devices

Question 11

udp/137

Answer 11

NetBIOS

• NetBIOS name service
• Register, remove, and find Windows services by name

Question 12

udp/138

Answer 12

NetBIOS

• NetBIOS datagram service
• Windows connectionless data transfer

Question 13

tcp/139

Answer 13

NetBIOS

• NetBIOS session service
• Windows connection-oriented data transfer

Question 14

tcp/445

Answer 14

SMB

• Server Message Block
• Windows file transfers and printer sharing

Question 15

tcp/548

Answer 15

AFP

• Apple Filing Protocol
• Mac OS file transfers

Question 16

tcp/427, udp/427

Answer 16

SLP

• Service Location Protocol
• Find Mac OS services by name

Question 17

udp/67, udp/68

Answer 17

DHCP

• Dynamic Host Configuration Protocol
• Automate the IP address configuration process

Question 18

tcp/389

Answer 18

LDAP

• Lightweight Directory Access Protocol
• Directory services

Question 19

udp/161

Answer 19

SNMP

• Simple Network Management Protocol
• Gathers metrics and manages network devices