Protocols & Ports Flashcards
For fast review of Port Numbers and what respective Protocols use them.
What is a Port?
Universally Relevant
A port is a virtual point where network connections start and end.
- Ports are software-based and managed by a computer’s operating system.
- Each port is associated with a specific process or service.
- Ports allow computers to easily differentiate between an array of protocols/traffic.
Thank you baby Jesus for Ports!
Universally Relevant
Ports 20 and 21
File Transfer Protocol (FTP)
* FTP Control = Port 21: Establishes the connection between the FTP client and server¹, where user authentication takes place², as well as the port for exchanging commands between the client and server³.
* FTP Data = Port 20: Used for transferring the actual file data, exclusively.
~Pizza Analogy~ Port 21 would be the phone line where you place your order, ask questions, and get confirmation -|- Port 20 then is the delivery person who brings the actual food (data) to your door.
Both Over TCP
Port 22
Secure Shell (SSH) uses Port 22.
* SSH is one of many tunneling protocols that create secure network connections.
The opposite of a Blue Shell… You know if you Know.
Over TCP
What port does SMTP use?
Simple Mail Transfer Protocol = Port 25
* SMTP has been historically used for email via Port 25, and although still used today, has a sketchy reputation due to it’s affiliation with spam and lack of mandatory encryption.
Over TCP
Hypertext Transfer Protocol (HTTP)
Port 80
What uses Port 123 ?
Network Time Protocol ~NTP is designed to synchronize the clocks of computer systems over a network. A process that is essential for many applications in many use cases such as academia, finance, science, and cybersecurity.
Port 179
Border Gateway Protocol (BGP).
* BGP is essential for establishing efficient routes between the large networks that make up the Internet (aka autonomous systems). Autonomous systems use BGP to broadcast which IP addresses they control.
HTTPS
Port 443
Over TCP
What is HTTPS ?
HTTPS is the secure and encrypted version of HTTP (Hyper Text Transfer Protocol). All HTTPS web traffic goes to port 443.
Over TCP
Port for POP3 ?
110
(over TCP)
Port 3389
RDP uses this port. Remote Desktop Protocol is a proprietary Windows protocol.
Over TCP
Port 587
SMTPS via TLS specifically
* Port 587 is the preferred and most secure port for sending email from your mail client. It’s the modern standard for email submission, offering encryption and authentication for better protection.
Over TCP + TLS
Port 53
Domain Name System (DNS)
* This one is a bit more nuanced than other protocols; DNS can use both TCP and UDP on port 53.
○ UDP is typically used for smaller queries and responses.
○ TCP is used for larger queries, zone transfers (exchanging DNS data between servers), and when reliability is important.
TCP or UDP
Wait, another Protocol with the same port?! Whaaaaaa
Port 22 {⨧}
…relies on SSH…
SCP!
Secure Copy Protocol is used for securely copying files between a local host and a remote host or between two remote hosts.
* It relies on the secure SSH channel for encryption & authentication.
○ SSH is primarily for remote access and command execution.
○ SCP is specifically designed for secure file transfer.
What port does Telnet use?
Telnet uses Port 23
* Telnet is a client-server protocol that allows you to remotely access and control another host PC over a network.
* Telnet is a legacy protocol that predates more secure protocols that have since replaced it, such as SSH
Over TCP
