Network+ 10-009 Objective 1.4: Common Networking Ports, Protocols, Services, and Traffic Types

September 9, 2025•28 min read•CompTIA Network+ Certification

Network+ Exam Focus: This objective covers essential networking protocols, their associated port numbers, services, and different traffic types. Understanding these concepts is fundamental for network troubleshooting, security implementation, and service configuration. Master these protocols and ports for both exam success and real-world network administration.

Introduction to Network Protocols and Ports

Network protocols define the rules and standards for communication between devices on a network. Each protocol operates on specific port numbers, which act as logical endpoints for network services. Understanding these protocols, their ports, and the services they provide is essential for network professionals.

Port Number Categories:

Well-Known Ports (0-1023): Reserved for system services and common applications
Registered Ports (1024-49151): Assigned by IANA for specific applications
Dynamic/Private Ports (49152-65535): Used for temporary connections

File Transfer Protocols

File Transfer Protocol (FTP) - Ports 20/21

FTP is a standard network protocol used for transferring files between a client and server over a network. It uses two separate connections: one for control commands and another for data transfer.

Key Characteristics:

Port 21: Control connection for commands and responses
Port 20: Data connection for file transfers
Connection Modes: Active and passive modes
Authentication: Username and password required
Security: Unencrypted (data sent in plain text)

Common Commands:

GET: Download files from server
PUT: Upload files to server
LIST: List directory contents
CD: Change directory
QUIT: Close connection

Secure File Transfer Protocol (SFTP) - Port 22

SFTP is a secure file transfer protocol that provides file access, transfer, and management over a secure connection. It encrypts both commands and data.

Key Characteristics:

Port 22: Same port as SSH
Encryption: All data encrypted using SSH
Authentication: Supports multiple authentication methods
Single Connection: Uses one connection for all operations
Firewall Friendly: Works through firewalls easily

Trivial File Transfer Protocol (TFTP) - Port 69

TFTP is a simple file transfer protocol that provides basic file transfer capabilities without authentication or encryption.

Key Characteristics:

Port 69: UDP-based protocol
No Authentication: No username/password required
Simple Protocol: Minimal overhead
UDP Transport: Connectionless protocol
Use Cases: Boot files, firmware updates, network device configuration

Remote Access Protocols

Secure Shell (SSH) - Port 22

SSH is a cryptographic network protocol for secure remote access and command execution over an unsecured network.

Key Characteristics:

Port 22: Standard SSH port
Encryption: Strong encryption for all communications
Authentication: Multiple authentication methods (password, key-based)
Features: Port forwarding, X11 forwarding, file transfer
Security: Replaces insecure protocols like Telnet

SSH Features:

Remote Login: Secure command-line access
File Transfer: SCP and SFTP capabilities
Port Forwarding: Tunnel other protocols through SSH
Key Management: Public/private key authentication
Session Management: Persistent connections

Telnet - Port 23

Telnet is a network protocol that provides bidirectional interactive text-oriented communication over a network.

Key Characteristics:

Port 23: Standard Telnet port
No Encryption: Data sent in plain text
Legacy Protocol: Older protocol, largely replaced by SSH
Interactive: Real-time command execution
Security Risk: Vulnerable to eavesdropping

Remote Desktop Protocol (RDP) - Port 3389

RDP is a proprietary protocol developed by Microsoft for providing remote display and input capabilities over network connections.

Key Characteristics:

Port 3389: Standard RDP port
Graphical Interface: Full desktop access
Encryption: Built-in encryption support
Platform: Primarily Windows-based
Features: Audio, clipboard, file transfer, printing

Email Protocols

Simple Mail Transfer Protocol (SMTP) - Port 25

SMTP is the standard protocol for sending email messages between servers and from clients to servers.

Key Characteristics:

Port 25: Standard SMTP port
Mail Sending: Used for sending emails
Server-to-Server: Communication between mail servers
Text-Based: ASCII-based protocol
No Encryption: Plain text by default

Simple Mail Transfer Protocol Secure (SMTPS) - Port 587

SMTPS is SMTP over SSL/TLS, providing encrypted email transmission for enhanced security.

Key Characteristics:

Port 587: Submission port with TLS
Encryption: TLS/SSL encryption
Authentication: Enhanced authentication support
Modern Standard: Preferred for email submission
Security: Protects email content and credentials

Web Protocols

Hypertext Transfer Protocol (HTTP) - Port 80

HTTP is the foundation of data communication for the World Wide Web, defining how messages are formatted and transmitted.

Key Characteristics:

Port 80: Standard HTTP port
Request-Response: Client-server communication model
Stateless: Each request is independent
Text-Based: Human-readable protocol
No Encryption: Plain text transmission

HTTP Methods:

GET: Retrieve data from server
POST: Submit data to server
PUT: Update existing resource
DELETE: Remove resource
HEAD: Get headers without body

Hypertext Transfer Protocol Secure (HTTPS) - Port 443

HTTPS is HTTP over SSL/TLS, providing encrypted and authenticated communication over a network.

Key Characteristics:

Port 443: Standard HTTPS port
Encryption: TLS/SSL encryption
Authentication: Server certificate verification
Data Integrity: Ensures data hasn't been tampered with
Modern Standard: Required for secure web communication

Network Services

Domain Name System (DNS) - Port 53

DNS is a hierarchical distributed naming system that translates domain names into IP addresses.

Key Characteristics:

Port 53: Both TCP and UDP
UDP: Standard DNS queries
TCP: Zone transfers and large responses
Hierarchical: Distributed database system
Recursive: DNS servers can query other servers

DNS Record Types:

A: IPv4 address record
AAAA: IPv6 address record
CNAME: Canonical name record
MX: Mail exchange record
NS: Name server record

Dynamic Host Configuration Protocol (DHCP) - Ports 67/68

DHCP is a network management protocol used to automatically assign IP addresses and other network configuration parameters to devices.

Key Characteristics:

Port 67: DHCP server
Port 68: DHCP client
UDP Protocol: Connectionless communication
Automatic Configuration: IP address, subnet mask, gateway, DNS
Lease Management: Temporary IP address assignments

DHCP Process (DORA):

Discover: Client broadcasts DHCP Discover
Offer: Server responds with DHCP Offer
Request: Client requests offered IP address
Acknowledge: Server confirms IP assignment

Network Time Protocol (NTP) - Port 123

NTP is a networking protocol for clock synchronization between computer systems over packet-switched networks.

Key Characteristics:

Port 123: UDP-based protocol
Time Synchronization: Keeps system clocks accurate
Hierarchical: Stratum levels for time sources
Precision: Sub-millisecond accuracy
Security: Authentication support available

Simple Network Management Protocol (SNMP) - Ports 161/162

SNMP is an Internet Standard protocol for collecting and organizing information about managed devices on IP networks.

Key Characteristics:

Port 161: SNMP agent (device being monitored)
Port 162: SNMP trap messages
UDP Protocol: Connectionless communication
Management Information Base (MIB): Database of managed objects
Versions: SNMPv1, SNMPv2c, SNMPv3

Directory Services

Lightweight Directory Access Protocol (LDAP) - Port 389

LDAP is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services.

Key Characteristics:

Port 389: Standard LDAP port
Directory Access: Read and write directory information
Authentication: User authentication and authorization
Hierarchical: Tree-like directory structure
Standards-Based: Open protocol standard

Lightweight Directory Access Protocol over SSL (LDAPS) - Port 636

LDAPS is LDAP over SSL/TLS, providing encrypted directory access for enhanced security.

Key Characteristics:

Port 636: LDAP over SSL/TLS
Encryption: All LDAP traffic encrypted
Security: Protects directory data and credentials
Certificate-Based: Server certificate validation
Modern Standard: Preferred for secure directory access

File Sharing and Database Protocols

Server Message Block (SMB) - Port 445

SMB is a network communication protocol for providing shared access to files, printers, and serial ports between nodes on a network.

Key Characteristics:

Port 445: Direct SMB over TCP/IP
File Sharing: Network file and printer sharing
Authentication: User-based access control
Versions: SMB1, SMB2, SMB3 with security improvements
Platforms: Windows, Linux, macOS support

Structured Query Language (SQL) Server - Port 1433

SQL Server uses port 1433 for database connections and communication between SQL Server instances and clients.

Key Characteristics:

Port 1433: Default SQL Server port
Database Access: Client connections to SQL Server
TCP Protocol: Reliable connection-oriented communication
Authentication: SQL Server and Windows authentication
Encryption: SSL/TLS encryption support

Logging and Communication Protocols

Syslog - Port 514

Syslog is a standard for message logging that allows separation of the software that generates messages from the system that stores them.

Key Characteristics:

Port 514: UDP-based protocol
Log Collection: Centralized logging system
Facility Codes: Categorize log messages
Severity Levels: Emergency, Alert, Critical, Error, Warning, Notice, Info, Debug
Network Devices: Routers, switches, firewalls use syslog

Session Initiation Protocol (SIP) - Ports 5060/5061

SIP is a signaling protocol used for initiating, maintaining, and terminating real-time communication sessions.

Key Characteristics:

Port 5060: Standard SIP port (UDP/TCP)
Port 5061: SIP over TLS
VoIP: Voice over IP communication
Session Management: Call setup, modification, termination
Text-Based: Human-readable protocol

Internet Protocol (IP) Types

Internet Control Message Protocol (ICMP)

ICMP is a supporting protocol in the Internet protocol suite used by network devices to send error messages and operational information.

Key Characteristics:

Protocol Number 1: IP protocol number
Error Reporting: Network error messages
Diagnostic Tools: Ping, traceroute functionality
No Port Numbers: Works at IP layer
Connectionless: No connection establishment

Common ICMP Messages:

Echo Request/Reply: Ping functionality
Destination Unreachable: Network or host unreachable
Time Exceeded: TTL expired (traceroute)
Redirect: Better route available
Source Quench: Congestion control

Transmission Control Protocol (TCP)

TCP is a connection-oriented protocol that provides reliable, ordered, and error-checked delivery of data between applications.

Key Characteristics:

Protocol Number 6: IP protocol number
Connection-Oriented: Establishes connection before data transfer
Reliable: Guarantees delivery and order
Flow Control: Manages data flow between sender and receiver
Error Detection: Checksums and acknowledgments

TCP Features:

Three-Way Handshake: SYN, SYN-ACK, ACK
Sequence Numbers: Ensures ordered delivery
Acknowledgments: Confirms data receipt
Window Size: Flow control mechanism
Connection Termination: Graceful connection closure

User Datagram Protocol (UDP)

UDP is a connectionless protocol that provides a simple, unreliable datagram service with minimal overhead.

Key Characteristics:

Protocol Number 17: IP protocol number
Connectionless: No connection establishment
Unreliable: No delivery guarantees
Low Overhead: Minimal protocol overhead
Fast: No acknowledgment delays

UDP Use Cases:

DNS Queries: Fast name resolution
DHCP: IP address assignment
Streaming Media: Real-time audio/video
Gaming: Low-latency game data
SNMP: Network management

Generic Routing Encapsulation (GRE)

GRE is a tunneling protocol that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links.

Key Characteristics:

Protocol Number 47: IP protocol number
Tunneling: Encapsulates various protocols
Point-to-Point: Virtual point-to-point links
No Encryption: Provides tunneling, not security
Flexible: Can carry multiple protocols

Internet Protocol Security (IPSec)

IPSec is a suite of protocols that provides security services at the IP layer, including authentication, integrity, and confidentiality.

Key Components:

Authentication Header (AH): Protocol number 51
Encapsulating Security Payload (ESP): Protocol number 50
Internet Key Exchange (IKE): Key management protocol

Authentication Header (AH)

Protocol Number 51: IP protocol number
Authentication: Verifies data integrity and sender identity
No Encryption: Does not encrypt data
Integrity Check: Prevents data tampering
Anti-Replay: Prevents replay attacks

Encapsulating Security Payload (ESP)

Protocol Number 50: IP protocol number
Encryption: Encrypts data for confidentiality
Authentication: Optional authentication service
Integrity: Ensures data hasn't been modified
Anti-Replay: Prevents replay attacks

Internet Key Exchange (IKE)

Port 500: IKE phase 1 (UDP)
Port 4500: IKE with NAT traversal (UDP)
Key Management: Establishes and manages security associations
Authentication: Authenticates peers
Negotiation: Negotiates encryption and authentication algorithms

Traffic Types

Unicast

Unicast is a one-to-one communication where data is sent from one source to one specific destination.

Characteristics:

One-to-One: Single source to single destination
Most Common: Standard point-to-point communication
Efficient Routing: Direct path to destination
Examples: Web browsing, email, file transfers
Bandwidth: Uses bandwidth proportional to number of recipients

Multicast

Multicast is a one-to-many communication where data is sent from one source to multiple specific destinations.

Characteristics:

One-to-Many: Single source to multiple destinations
Group-Based: Recipients join multicast groups
Efficient: Single stream replicated at network nodes
Examples: Video streaming, software updates, stock quotes
IP Range: 224.0.0.0 to 239.255.255.255

Anycast

Anycast is a one-to-one-of-many communication where data is sent to the nearest or best destination from a group of potential destinations.

Characteristics:

One-to-Nearest: Single source to closest destination
Load Distribution: Distributes load across multiple servers
High Availability: Automatic failover to backup servers
Examples: DNS root servers, CDN edge servers
Routing: Uses standard routing protocols

Broadcast

Broadcast is a one-to-all communication where data is sent from one source to all devices on a network segment.

Characteristics:

One-to-All: Single source to all destinations
Network Segment: Limited to local network segment
No Routing: Routers do not forward broadcasts
Examples: ARP requests, DHCP discovery
IPv4: 255.255.255.255 (limited broadcast)

Protocol and Port Summary Table

Protocol/Service	Port(s)	Transport	Purpose
FTP	20/21	TCP	File Transfer
SSH/SFTP	22	TCP	Secure Remote Access
Telnet	23	TCP	Remote Access
SMTP	25	TCP	Email Sending
DNS	53	UDP/TCP	Name Resolution
DHCP	67/68	UDP	IP Configuration
TFTP	69	UDP	Simple File Transfer
HTTP	80	TCP	Web Browsing
NTP	123	UDP	Time Synchronization
SNMP	161/162	UDP	Network Management
LDAP	389	TCP	Directory Services
HTTPS	443	TCP	Secure Web Browsing
SMB	445	TCP	File Sharing
Syslog	514	UDP	Logging
SMTPS	587	TCP	Secure Email
LDAPS	636	TCP	Secure Directory
SQL Server	1433	TCP	Database Access
RDP	3389	TCP	Remote Desktop
SIP	5060/5061	UDP/TCP	VoIP Signaling

Common Exam Scenarios

Network+ exam questions often test your knowledge of protocols, ports, and traffic types in practical scenarios. Here are common topics:

Scenario-Based Questions:

Port Identification: Identifying which port a service uses
Protocol Selection: Choosing appropriate protocol for specific needs
Traffic Analysis: Understanding different traffic types
Security Implementation: Using secure vs. insecure protocols
Troubleshooting: Identifying protocol-related issues

Study Tips for Network+ Objective 1.4

Key Study Points:

Memorize Port Numbers: Know the common ports and their protocols
Understand Protocol Functions: Know what each protocol does
Transport Layer Knowledge: Understand TCP vs. UDP characteristics
Security Implications: Know secure vs. insecure protocols
Traffic Types: Understand unicast, multicast, anycast, broadcast
IP Protocol Numbers: Know ICMP, TCP, UDP, GRE, IPSec numbers

Conclusion

Understanding networking protocols, ports, services, and traffic types is fundamental to network administration and troubleshooting. Each protocol serves specific purposes and operates on designated ports, making it essential for network professionals to know these details.

The choice between different protocols depends on specific requirements including security, reliability, performance, and functionality. Understanding the characteristics of TCP vs. UDP, the different traffic types, and the security implications of various protocols is crucial for designing and maintaining secure, efficient networks.

Next Steps: Practice identifying protocols and ports in real-world scenarios. Understanding when to use secure vs. insecure protocols and how different traffic types affect network performance will help you make informed decisions in network design and troubleshooting situations.