Common Ports, Protocols, and Services

Section 1.4

Well known ports

Ports 1-1023

1024-49151

Registered port numbers reserved for company protocols

49152-65535

Dynamic or private ports

20/21

Port used for File Transfer Protocol (FTP)

What does File Transfer Protocol (FTP) use port 20 for?

Port 20 for data transfer

What does File Transfer Protocol (FTP) use port 21 for?

Port 21 for control (commands and responses)

What is File Transfer Protocol(FTP) 20/21?

Is a standard network protocol used for the transfer of computer files between a client and server on a computer network

What can File Transfer Protocol(FTP) 20/21 be used to do?

Allows users to upload, download, delete, and manage files on a remote server but does not encrypt traffic including credentials

What is Secure File Transfer Protocol (SFTP) 22?

is an extension of SSH to provide a secure method for transferring files

What port does Secure File Transfer Protocol (SFTP) use?

Port 22

How does Secure File Transfer Protocol (SFTP) 22 encrypt data?

Utilizes SSH’s port 22 to ensure all data and commands are encrypted and secure providing a more secure alternative to traditional FTP

SSH (Secure Shell) 22

a cryptographic network protocol for operating network services securely over an unsecured network

SSH (Secure Shell)

Port 22

SSH traffic encryption

encrypts all traffic (including passwords) to effectively eliminate eavesdropping, connection hijacking and other network level attacks

Telnet

uses port 23

Telnet 23

a network protocol used on the internet or local area network to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection

What port does Telnet use?

Port 23

How does communication happen when using Telnet 23?

Virtual terminal connections

Replaced by SSH (Secure Shell) 22

What has Telnet been replaced by because of its vulnerabilities?

What are the vulnerabilities when using Telnet?

No encryption, all communications can be seen in plain text

What is Telnet used for primarily?

Configure network devices virtually

Simple Mail Transfer Protocol (SMTP) 25

the standard protocol for email transmission across the internet

What port does Simple Mail Transfer Protocol (SMTP) use?

Port 25

What does Simple Mail Transfer Protocol (SMTP) 25 do?

sending messages from an email client to an email server between servers

Simple Mail Transfer Protocol (SMTP) 25 is used for

primarily for sending emails

POP3 or IMAP

protocols is used for email retrieval

Simple Mail Transfer Protocol (SMTP) 25 secure or insecure?

Insecure

DNS 53

Domain name system 53

protocol used at port 53

domain name system DNS (53)

Domain Name System translation

translates domain names to numerical IP addresses

domains can alternatively be identified by

IP address because of DNS protocol

Protocol

a set of rules for formatting and processing data

DNS (53)

associates various information with domain names assigned to participating entities and uses port 53 for queries

Dynamic Host Configuration Protocol (DHCP) 67/68

network management protocol on a DHCP server used to dynamically assigns an IP address and other network configuration parameters to each device on a network

what port does DHCP use?

67 & 68

UDP (Server) 67

DHCP operates on UDP ports 67 server

UCP (Client) 68

DHCP operates on UDP port 68 client

DHCP 67/68

facilitates automatic and centralized management of IP addressing

Dynamic Host Configuration Protocol (DHCP) 67/68

allows devices to join a network and obtain valid IP addresses, subnet masks, gateways, and DNS server information without manual configuration

Trivial file transfer protocol (TFTP) 69

simple file transfer protocol

DHCP automatically assigns

subnet mask, gateways, IP address, DNS server

TFTP 69

used for transferring files smaller in size

Port 69

Trivial file transfer protocol (TFTP)

uses UDP port 69