CompTIA A+ Port Numbers

Cards · 50

Port 20 (TCP)

FTP (Data Transfer) - Used by File Transfer Protocol to transfer actual file data between client and server.

Port 21 (TCP)

FTP (Control) - Used by File Transfer Protocol to send commands and control connections.

Port 22 (TCP)

SSH / SFTP - Secure Shell provides encrypted remote command-line access; also used by Secure FTP.

Port 23 (TCP)

Telnet - Provides unencrypted remote command-line access to network devices and servers.

Port 25 (TCP)

SMTP - Simple Mail Transfer Protocol sends outgoing email between mail servers or from a client to a server.

Port 53 (TCP/UDP)

DNS - Domain Name System resolves human-friendly hostnames to numeric IP addresses.

Port 67 (UDP)

DHCP Server - Dynamic Host Configuration Protocol port listened to by servers to receive client IP requests.

Port 68 (UDP)

DHCP Client - Dynamic Host Configuration Protocol port listened to by clients to receive IP configurations.

Port 69 (UDP)

TFTP - Trivial File Transfer Protocol provides a lightweight, connectionless file transfer without authentication.

Port 80 (TCP)

HTTP - Hypertext Transfer Protocol transmits unencrypted web page content across the internet.

Port 88 (TCP/UDP)

Kerberos - Network authentication protocol that uses secret-key cryptography for mutual authentication.

Port 110 (TCP)

POP3 - Post Office Protocol version 3 retrieves email from a remote server, usually deleting it from the server.

Port 123 (UDP)

NTP - Network Time Protocol synchronizes system clocks across devices on a network.

Port 137 (UDP)

NetBIOS Name Service - Used for name registration and resolution on legacy NetBIOS networks.

Port 138 (UDP)

NetBIOS Datagram Service - Delivers connectionless datagram traffic between NetBIOS systems.

Port 139 (TCP)

NetBIOS Session Service - Provides connection-oriented communication and file/print sharing over NetBIOS.

Port 143 (TCP)

IMAP - Internet Message Access Protocol retrieves email while keeping messages synchronized on the mail server.

Port 161 (UDP)

SNMP Queries - Simple Network Management Protocol used by managers to monitor and query network device metrics.

Port 162 (UDP)

SNMP Traps - Used by managed network devices to send unsolicited alert and status notifications to managers.

Port 389 (TCP/UDP)

LDAP - Lightweight Directory Access Protocol queries and manages directory information services over a network.

Port 443 (TCP)

HTTPS - Hypertext Transfer Protocol Secure transmits encrypted web traffic using TLS/SSL.

Port 445 (TCP)

SMB - Server Message Block provides shared access to files, printers, and serial ports over TCP/IP.

Port 465 (TCP)

SMTPS - Simple Mail Transfer Protocol Secure sends encrypted outgoing email over TLS/SSL.

Port 514 (UDP)

Syslog - Transmits system log and event notifications from network devices to a central collector.

Port 587 (TCP)

SMTP Secure Submission - Standard modernized port for email clients to submit outgoing mail securely over TLS.

Port 636 (TCP)

LDAPS - Lightweight Directory Access Protocol Secure queries directory services using TLS/SSL encryption.

Port 993 (TCP)

IMAPS - Internet Message Access Protocol Secure retrieves and synchronizes email encrypted via TLS/SSL.

Port 995 (TCP)

POP3S - Post Office Protocol 3 Secure retrieves email using an encrypted TLS/SSL connection.

Port 1433 (TCP)

Microsoft SQL Server - Default port for incoming relational database client connections to Microsoft SQL.

Port 1521 (TCP)

Oracle Database - Default listener port for incoming client connections to an Oracle database.

Port 1720 (TCP)

H.323 - Call signaling protocol used to initiate and manage VoIP and videoconferencing sessions.

Port 1812 (UDP)

RADIUS Authentication - Remote Authentication Dial-In User Service port used to verify user credentials.

Port 1813 (UDP)

RADIUS Accounting - Collects session runtime and accounting statistics for network access management.

Port 3306 (TCP)

MySQL - Default network listening port for client queries to the MySQL database engine.

Port 3389 (TCP/UDP)

RDP - Remote Desktop Protocol enables graphical remote control of a Windows-based operating system.

Port 5060 (TCP/UDP)

SIP - Session Initiation Protocol initializes, manages, and terminates VoIP and multimedia sessions unencrypted.

Port 5061 (TCP)

SIPS - Session Initiation Protocol Secure encrypts VoIP call signaling using TLS.

Port 5353 (UDP)

mDNS - Multicast DNS resolves hostnames within small, localized networks without a dedicated DNS server.

Port 5432 (TCP)

PostgreSQL - Standard port for client connections to the PostgreSQL open-source database engine.

Port 8080 (TCP)

HTTP Alternate / Proxy - Frequently used as a secondary web server port or for HTTP proxy and caching services.

Port 8443 (TCP)

HTTPS Alternate - Common alternative port for hosting secure web interfaces and administration consoles.

Port 49 (TCP/UDP)

TACACS+ - Terminal Access Controller Access-Control System Plus provides centralized AAA security for network devices.

Port 119 (TCP)

NNTP - Network News Transfer Protocol handles the distribution and retrieval of Usenet newsgroup posts.

Port 500 (UDP)

IKE / ISAKMP - Internet Key Exchange sets up security associations and cryptographic keys for IPsec VPNs.

Port 1701 (UDP)

L2TP - Layer 2 Tunneling Protocol creates VPN tunnels, typically paired with IPsec for encryption.

Port 1723 (TCP)

PPTP - Point-to-Point Tunneling Protocol provides legacy VPN tunnels using unencrypted control sessions.

Port 4500 (UDP)

IPsec NAT-T - Traverses Network Address Translation routers for encrypted IPsec VPN traffic.

Port 5900 (TCP)

VNC - Virtual Network Computing provides platform-independent graphical desktop sharing.

Port 2049 (TCP/UDP)

NFS - Network File System allows a user to access files over a network as if on local storage.

Port 631 (TCP)

IPP - Internet Printing Protocol manages print jobs and printer status queries across local and remote networks.