Ports

Question 1

Well-Known Ports

Answer 1

Ports 0 to 1023 are considered well-known and are assigned by the Internet Assigned Numbers Authority (IANA)

Question 2

Registered Ports

Answer 2

Ports 1024 to 49,151 are registered with IANA and are the usually assigned to proprietary protocols.

Question 3

Dynamic or Private Ports

Answer 3

Ports 49,152 to 65,535 can be used by any application without being registered with IANA. Usually used for temporary outbound connections, gaming and instant message chats.

Question 4

FTP

Answer 4

File Transfer Protocol; Port 20, 21

Transfers computer files between a client and a server on a computer network; data is in the clear.

Question 5

SSH

Answer 5

Secure Shell; Port 22
Secure remote control of another machine using a text-based environment.
Cryptographic network protocol for operating network services securely over an unsecured network; best know for remote login to computer systems using a command shell

Question 6

SFTP

Answer 6

SSH File Transfer Protocol; Port 22

Using FTP for file access, file transfer, and file management through a secure shell tunnel.

Question 7

Telnet

Answer 7

Telnet; Port 23
Insecure remote access via a command prompt. Very similar to SSH, but it is not secure; everything is sent in the clear (not encrypted). It should never be used on an insecure network (like the internet) because username, password, everything is in the clear.

Question 8

SMTP

Answer 8

Simple Mail Transfer Protocol; Port 25

Internet standard for sending electronic messages. Think SMTP when sending mail.

Question 9

DNS

Answer 9

Domain Name Service; Port 53
DNS converts domain names to IP addresses or IP addresses to domain names.
Hierarchical, decentralized naming system for computer, services, or other resources connected to the internet or a private network.

Question 10

DHCP

Answer 10

Dynamic Host Control Protocol; Port 67, 68

DHCP automatically assigns IP addresses and other network configuration parameters to network clients.

Question 11

TFTP

Answer 11

Trivial File Transfer Protocol; Port 69
Transmits files in both directions (client to server AND server to client) using an application. Usually used for requesting configuration files from a router or a switch or booting up an operating system from a network drive. It doesn’t provide any authentication.
It’s basically a stripped down version of FTP.

Question 12

HTTP

Answer 12

Hypertext Transfer Protocol; port 80 - unsecured web-browsing.

Question 13

POP3

Answer 13

Post Office Protocol v3; Port 110
Used by local email clients to retrieve emails from a remote server over TCP connection.
Think downloading email files to your computer so you can read it offline.

Question 14

NTP

Answer 14

Network Time Protocol; Port 123
Clock sync between computer systems (additional detail: clock sync over packet-switched, variable-latency data networks).
Remember: Port 123, like keeping time.

Question 15

NetBIOS

Answer 15

Network Basic Input/Output System; Port 139
NetBIOS provides services allowing applications on separate computers to communicate over a LAN connection for file and printer sharing

Question 16

IMAP

Answer 16

Internet Mail Application Protocol; Port 143
IMAP allows a client to retrieve email from a mail server over a TCP connection; the users can view and manipulate messages as if they were on the locally while still leaving the messages on the remote system. IMAP keeps all your devices synced RE what emails have been read. IMAP is best for modern email. POP3 isn’t used by most people, but it is still used for server to server email sometimes.
Remember: Port 143, receive emails.
POP3 can also be used to receive emails.
Sending emails is SMTP over port 25.

Question 17

SNMP

Answer 17

Simple Network Management Protocol; Port 161

SNMP collects and organizes information about managed devices on your IP networks (like routers and switches).

Question 18

LDAP

Answer 18

Lightweight Directory Access Protocol; Port 389
Open, vendor-neutral, indurstyr standard for accessing and maintaining a distributed directory of inormatino services. LDAP and Active Directory both use port 389.
Remember: it’s a directory, like a phone book

Question 19

HTTPS

Answer 19

HTTP Secure; port 443
Adds security (TLS or SSL) to the insecure HTTP Protocol

Question 20

SMB

Answer 20

Server Message Block; Port 445
SMB provides shared access to files, printers, and misc communications between deives on a network.
SMB is used together with NetBIOS.
NetBIOS is more focused on the authentication;
SMB sends the files to you.

Question 21

LDAPS

Answer 21

LDAP Secure; Port 636

Just like LDAP, but adding encription (TLS/SSL) to make it more secure.

Question 22

RDP

Answer 22

Remote Desktop Protocol; Port 3389
Proprietary protocol by Microsoft with provides a users with a graphical interface to connect to another computer over a network connection.
SSH or Telnet allows you a command line way to control another computer.
RDP allows you to use a keyboard and mouse to control that other computer.

Question 23

SIP

Answer 23

Session Initiation Protocol; Port 5060, 5061
Provides signaling and controlling multimedia communication sessions in applications. Used for VOIP, video calls, voice calls, and instant messaging.

Question 24

VNC

Answer 24

Virtual Network Computing; Port 5900
Designed for things like VDI.
Works like RDP, but it works for all platforms (Windows, Linux, and Mac OS