Server Ports Basics You Must Know

Updated on Aug 11, 2022 by

In network technology, server ports are categorized into physical ports and logical ports, also known as virtual ports. Physical ports, like Ethernet, LAN, and USB ports, serve as connectors for various network devices such as ADSL modems, hubs, switches, and routers. On the other hand, logical ports primarily pertain to TCP/IP protocol ports, distinguished by port numbers ranging from 0 to 65535. Examples include port 80 for web browsing services and port 21 for FTP services. Let's delve into the definition, classification, and methods to identify the open logical ports on a server.


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What Are Server Physical Ports?

Server physical ports, integral components among server ports, encompass visual interfaces and input/output connectors essential for establishing communication between a server and other devices or computer networks. Various types of physical ports found on servers include VGA ports, IPMI ports, Ethernet ports, USB ports, and serial ports.

  • VGA Ports: Serving as a graphics card interface, the VGA port facilitates the transmission of video signals, significantly contributing to visual display capabilities. Simultaneously, the IPMI port, also known as the Intelligent Platform Management Interface port, plays a crucial role in server management.

  • Ethernet Ports: Essential for networking, Ethernet ports establish connections between servers and computer network equipment. The server LAN port, commonly linked to a router, plays a pivotal role in creating wired network connections across local area networks, metropolitan area networks, and wide area networks.

  • USB (Universal Serial Bus) Ports: Found on servers, USB ports provide connectivity for devices like mice, 4U chassis, and keyboards. With plug-and-play and hot-swappable functionality, server USB ports enhance convenience for tasks such as file copying and plug-in installations.

  • Server Serial Ports: Including COM ports, these ports function as standard cable interfaces. Enabling data transmission between serial ports and network devices like switches and microcomputers, the serial port empowers users to access, manage, and configure remote devices over the network using their computers.

server ports

What Are Server Logical Ports?

In response to the evolving demands of communication networks, the traditional physical ports of server ports are facing limitations. To address this, logical ports, commonly referred to as TCP/IP protocol ports, have emerged as a contemporary solution. These logical ports are categorized based on their distinct properties and services, each catering to specific needs and functionalities within the network.

Server Ports by Properties

With the development of communication networks, the physical ports of server ports can no longer meet network requirements, giving rise to logical ports. Logical ports, also known as TCP/IP protocol ports, are classified into various types based on their properties and services. Each of them provides different services.

      • Well-known Ports: Ranging from 0 to 1023, well-known ports are dedicated to specific services, adhering to predefined service protocols on servers.

      • Registered Ports: Falling between 1024 and 49151, registered ports are also associated with server services. However, these ports lack clearly defined service objects, allowing different applications to redefine them based on their requirements.

      • Dynamic / Private ports: Spanning from 49152 to 65535, dynamic or private ports are typically not allocated for common services. These ports are considered vulnerable to Trojan horse attacks, and caution is advised in their use.

Server Ports by Services

If categorized based on the different service modes, ports can be further divided into two types: "TCP protocol ports" and "UDP protocol ports." This is because computers typically communicate with each other using the TCP and UDP communication protocols. You can click here to view the list of server TCP ports and UDP ports.

TCP Protocol

Transmission Control Protocol (TCP) stands as a foundational connection-oriented communication protocol. This protocol plays a pivotal role in enabling computing devices and applications to transmit data across networks while ensuring its delivery. TCP is integral to the seamless functioning of the global internet. The common ports used with the TCP protocol include the following:

      • FTP (File Transfer Protocol): Operating on the seventh layer of the OSI model and the fourth layer of the TCP model (application layer), FTP is a set of standard protocols for network file transfer. Users can communicate with another host using file operations through the FTP protocol.

      • Telnet: This port serves remote login purposes, allowing users to connect to a computer remotely using their own identity through servers. Telnet provides a communication service based on DOS mode.

      • SMTP: Ensuring high-reliability email transmission, SMTP operates as a mail transfer service built on the FTP file transfer service. Primarily used for transferring mail information between systems, SMTP notifies users about incoming letters, hence its association with mail servers.

      • POP3: Used for receiving mail and corresponding to SMTP, POP3 operates on port 110. When servers have the appropriate POP3 protocol program, users can receive mail through their mail program.

UDP Protocol

The UDP protocol within server ports operates as a connectionless transmission control protocal situated in the OSI reference model. Primarily utilized in data services where packet transmission order is not critical, UDP is applicable to multiple applications concurrently running on a server. Noteworthy UDP port numbers encompass 53 (DNS), 69 (TFTP), and 161 (SNMP). Prominent applications utilizing UDP protocols include TFTP, SNMP, NFS, DNS, and BOOTP.

TCP/UDP ports

Difference Between TCP and UDP

The TCP and UDP protocol ports on the server ports provide different services for a wide variety of devices connected to the server, which allows them to coexist under the same IP address. So what is the difference between the TCP protocol port and the UDP protocol port? Here is the answer.

Difference Between TCP and UDP

      • TCP ports provide a more reliable service link because they must establish endpoints between sending and receiving locations. These ports keep track of data, ensuring that packets are delivered to recipients in a safe and orderly manner.

      • UDP ports boast faster connection speeds but with relatively lower reliability. These ports permit data to be sent out of order and lack the tracking and inspection capabilities found in TCP ports. They are primarily employed for speed-critical operations, including online gaming or video conferencing.

Checking Open Logical Ports on the Server

To retrieve information about your server ports, you can utilize the Netstat command on your computer. Netstat is commonly employed to present statistical data concerning IP, TCP, UDP, and ICMP protocols, offering insights into the network connections associated with each server port on the machine. Functioning as a program accessing network and kernel-related information, Netstat delivers comprehensive reports on TCP connections, TCP and UDP monitoring, and process memory management.


Understanding your server port information is crucial for maintaining control over your applications. Since different applications rely on specific server ports, monitoring them becomes essential for ensuring system stability. In cases where certain ports are inactive or unusable, prompt attention and troubleshooting are necessary. Additionally, opening a port through router configurations can be a solution for directing traffic to specific devices or applications. It's important to highlight that manipulating certain ports may be required to navigate firewalls and prevent hindrances to their functionality.

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