Common Ports

Question 1

FTP

Answer 1

20/21: File Transfer Protocol. Insecure File Transfer between two devices.

Question 2

SSH

Answer 2

22: Secure Shell is a secure telnet session for logging into other systems, running programs and commands, and moving files from one system to another.

Question 3

SFTP

Answer 3

22: Secure FTP. It’s encrypted file transfer.

Question 4

Telnet

Answer 4

23: Insecure terminal that allows you to access resources of another machine, run commands, and remotely access a system.

Question 5

SMTP

Answer 5

25: SEND email over the network with a spooled/queued message delivery.

Question 6

DNS

Answer 6

53: Resolves hostnames to corresponding IP

Question 7

DHCP

Answer 7

67,68: Automatically assigns device IP to a host/device for easier administration.

Question 8

TFTP

Answer 8

69: Lightweight file transfer protocol for fast transfers and network booting.

Question 9

HTTP

Answer 9

80: Insecure web communication for browsers and web servers.

Question 10

POP3

Answer 10

110: Receiving email (Incoming mail). Older than IMAP.

Question 11

NTP

Answer 11

123: Time protocol that is used for accuracy and synchronization.

Question 12

NetBios

Answer 12

139: File/Printer Sharing protocol for windows.

Question 13

IMAP

Answer 13

143: New(er) method of retrieving emails, now replacing POP3 as a better option. More security and can download only parts of a message.

Question 14

SNMP

Answer 14

161,162: Used for network data collection and manipulation.

Question 15

LDAP

Answer 15

389: Lightweight Directory Access Protocol. Directory services for devices and users for system administration. Query directory services such as AD DS.

Question 16

HTTPS

Answer 16

443: Secure version of the web browsing/server protocol (TLS/SSL)

Question 17

SMB

Answer 17

445: Server Message Block. Used for sharing access to files and printers and other communications between hosts(devices, etc.) on a network.

Question 18

SYSLOG

Answer 18

514: System Logs. Display, sort, and search messages for troubleshooting and documentation. Read system messages from a switch or router, Use this port for a syslog server which track what’s happening (Can do time stamps, sequence, etc.)

Question 19

SMTP TLS

Answer 19

587: Simple Mail Transfer Protocol TLS. Encrypts email when it’s sent and ensures secure delivery.

Question 20

LDAPS

Answer 20

636: Secure version of LDAP over SSL. Suggested over port 386. Must install proper certificate to get it to work from a CA.

Question 21

IMAP / SSL

Answer 21

993: Secure IMAP with SSL.

Question 22

POP3 / SSL

Answer 22

995: Secure POP3 with SSL.

Question 23

SQL

Answer 23

1433: Microsoft SQL default port number for client systems.

Question 24

SQLnet

Answer 24

1521: Oracle’s SQL default port number for remote data access. No longer needed.

Question 25

MySQL

Answer 25

3306: Open source SQL server for same use case as the other SQL ports.

Question 26

RDP

Answer 26

3389. Remote Desktop Protocol. Microsoft developed protocol that allows GUI and remote control of a device.

Question 27

SIP

Answer 27

5060(TCP or UDP)/5061(TCP): Signaling protocol for VOIP and video calls and multimedia communication sessions. (Video conference, streams, IM, online games, etc.)