CompTIA A+/Network+ Ports

Learn these Ports as they will be mentioned in both certification exams

Port 20/21

(FTP) is used for File Transfer Protocol. Port 20 is used for data transfer, while port 21 is used for command control. It enables users to upload and download files over a network. TCP

Port 22

(SSH)is used for Secure Shell, providing a secure channel for remote command execution and secure file transfers. TCP

Port 23

(Telnet)is a network protocol used for text-based communication over a TCP/IP network. It allows users to establish a command-line interface on a remote device. TCP

Port 53

(DNS)is used for Domain Name System, which translates domain names into IP addresses. TCP/UDP

Port 67,68

(DHCP)Dynamic Host Configuration Protocol: Dynamically assigns IP address information (for example, IP address, subnet mask, DNS server's IP address, and default gateway's IP address) to a network device over a network automatically, simplifying the administration of IP addresses. UDP

Port 69

(TFTP) Trivial File Transfer Protocol: A very simple file transfer protocol without authentication or encryption. Often used in network booting or router firmware updates. UDP

Port 80

(HTTP) Hypertext Transfer Protocol: Retrieves content from a web server. The foundation of the World Wide Web, used for unencrypted web browsing. TCP

Port 110

(PoP3) Post Office Protocol v3: Retrieves emails from a server to a client, typically removing them from the server once downloaded. TCP

Port 123

(NTP) Network Time Protocol: Keeps clocks synchronized across devices and servers on a network, critical for security certificates and logging.

Port 139

NetBIOS/NetBT: An older Windows protocol for file and printer sharing. Superseded by SMB but still seen in legacy systems. TCP/UDP

Port 143

(IMAP) Internet Message Access Protocol: Retrieves emails while keeping them on the server, allowing syncing across multiple devices. TCP

Port 161, 162

(SNMP) Simple Network Management Protocol: Allows monitoring and management of network devices (like routers, switches, printers) using status messages

1st port #(UDP) → Used for SNMP queries/requests

2nd port # (UDP) → Used for SNMP traps/notifications

Port 389

LDAP (Lightweight Directory Access Protocol): Used for accessing and maintaining directory information services, such as Active Directory for authentication and user management. TCP,UDP

TCP= Full LDAP communication (authentication, directory queries)

UDP = Quick lookups/ discovery (“Who is my directory server?“)

Port 443

HTTPS (HTTP Secure): Secure version of HTTP, encrypting all web traffic using SSL/TLS. Standard for secure web browsing, online banking, etc. TCP

Port 445

SMB/CIFS (Server Message Block)
Used for Windows file and printer sharing in modern networks. Replaced much of NetBIOS functionality. TCP

Port 514

Syslog
Used for system logging — devices and applications send log data to a centralized logging server for monitoring and auditing. TCP/UDP

TCP = Reliable, ordered, can be encrypted, used when logs are mission-critical.

UDP = Default, Fast, lightweight, good for high-volume logs, but unreliable.

Port 587

(SMTP TLS) Simple Mail Transfer Protocol Transport Layer Security:

A secure way for email clients to send mail to servers (uses TLS encryption). Often replaces port 25 for client-to-server email submission. TCP

Port 636

LDAPS (LDAP over SSL)
Secure version of LDAP, encrypts directory service communications. TCP

Port 993

IMAPS (IMAP over SSL)
Secure version of IMAP, encrypting email retrieval. TCP

Port 995

POP3S (POP3 over SSL)
Secure version of POP3, encrypting email downloads. TCP/UDP

Port 1433

SQL Server
Default port for Microsoft SQL Server database connections. TCP

Port 1521

Oracle SQL Net
Default port for Oracle databases, allows client applications to connect. TCP/UDP

Port 3306

MySQL
Default port for MySQL database service. TCP

Port 3389

RDP (Remote Desktop Protocol)
Allows remote graphical login to Windows systems. Commonly used for system administration.

Port 5060, 5061

SIP / Secure SIP (Session Initiation Protocol)
Used to establish, manage, and terminate VoIP (Voice over IP) calls and video conferencing. Second is the encrypted version.