What is a Port ?
- logical connection point that allows devices to communicate with one another.
- A port is a 16-bit number (0-65535) that identifies a specific process or service running on a network device.
- Port 0 reserved and not used.
- IANA assigns port numbers
What are the 3 port ranges ?
- Well-known ports (0-1023): Standardized ports for common services (e.g., HTTP:80, FTP:21)
- Registered ports (1024-49151): Assigned by IANA for specific services
- Private ports (49152-65535): Available for custom use
What are the functions of Ports ?
- Service identification: Identifies the service or process running on a device
- Connection establishment: Enables devices to establish connections
- Data routing: Directs data to the correct process or service
Name the following TCP Ports: 80, 443, 21, 22
- HTTP: 80 (Web servers)
- HTTPS: 443 (Secure web servers)
- FTP: 21 (File Transfer Protocol)
- SSH: 22 (Secure Shell)
Name the following TCP Ports: 25, 53, 161, 23.
- SMTP: 25 (Simple Mail Transfer Protocol)
- DNS: 53 (Domain Name System)
- SNMP: 161 (Simple Network Management Protocol)
- Telnet: 23 (Remote access)
Name the following UDP Ports: 67-68, 161-162, 69, 123
- DHCP: 67-68 (Dynamic Host Configuration Protocol)
- SNMP: 161-162 (Simple Network Management Protocol)
- TFTP: 69 (Trivial File Transfer Protocol)
- NTP: 123 (Network Time Protocol)
Name the following Ports: 500, 119, 3389, 389
- Port 500:
IPSec (Internet Protocol Security)
IKE (Internet Key Exchange)
ISAKMP (Internet Security Association and Key Management Protocol) - Port 119:
NNTP (Network News Transfer Protocol)
Usenet news - Port 3389:
RDP (Remote Desktop Protocol)
Microsoft Terminal Services - Port 389:
LDAP (Lightweight Directory Access Protocol)
Directory services (e.g., Active Directory)
What is File Transfer Protocol (FTP) ?
List 7 FTP commands.
List 4 FTP modes.
- Binary mode: Transfers files in binary format.
- ASCII mode: Transfers text files in ASCII format.
- Active mode: FTP server initiates data transfer.
- Passive mode: FTP client initiates data transfer.
List 4 FTP types
- FTP (File Transfer Protocol): Standard FTP.
- SFTP (Secure File Transfer Protocol): Secure, encrypted FTP.
- FTPS (FTP over SSL/TLS): FTP over secure socket layer.
- TFTP (Trivial File Transfer Protocol): Simple, non-secure FTP.
What are the default FTP Port numbers ?
- Command port: 21 (default)
- Data port: 20 (default)
What is Simple Mail Transfer Protocol (SMTP) ?
- Is a push protocol used for sending and receiving email messages between email servers and clients.
What are the key features of SMTP ?
- Mail transfer: Sends and receives email messages.
- Relaying: Forwards email messages to next-hop servers.
- Mail routing: Routes email messages to destination servers.
- Authentication: Optional authentication mechanisms.
- Error handling: Returns error messages for undeliverable emails.
What ports do SMTP use ?
- Default port: 25 (non-secure)
- Secure port: 465 (SSL/TLS encrypted)
- Submission port: 587 (authenticated submissions)
List 3 SMTP response codes
- 2xx: Success
- 4xx: Temporary failure
- 5xx: Permanent failure
What port is DHCP ?
Dynamic Host Configuration Protocol
Ports: 67 ~
:68 ~
What port is SNMP ?
Simple Netw
161-162
What is Port 80 ?
- HTTP - Hypertext Transfer Protocol
- Not encrypted
What is port 443 ?
HTTPS - Hypertext Transfer Protocol Secure.
Encrypted using SSL/TLS
What is port 21?
Port 21 is the default network port used by FTP (File Transfer Protocol).
What it’s used for
FTP control connection
Handles commands like:
login (username/password)
directory listing
file upload/download requests
Not Secure
What is port 22?
Port 22 is the default network port used by SSH (Secure Shell).
What it’s used for
- Secure remote login to another computer/server
- Command-line control of servers
- Secure file transfer via:
- SFTP (SSH File Transfer Protocol)
- SCP (Secure Copy)
What is the port number for HTTPS ?
Hypertext Transfer Protocol Secured
Port 443
