10/11/2024 | News release | Distributed by Public on 10/11/2024 10:01
Think of a port as a virtual gateway that a specific service, process, or application on your computer uses for network communication. Each port is assigned a unique number, allowing different types of traffic to be directed to the appropriate software. For example, your email might use one port, while your web browsing uses another. When combined with an IP address, a port number creates a complete socket address, enabling precise routing of data to and from your computer across the network
Ports help computers sort the network traffic they receive, ensuring that different types of traffic are directed to the correct applications. Ports allow different services or applications on the same device to communicate with each other and with external systems.
Network ports are categorized into three main ranges, each serving distinct purposes in network communication. Most ports are permanently assigned as Well-Known Ports or Registered Ports. By the Internet Assigned Numbers Authority (IANA). The IANA is responsible for the global coordination of port number assignments and maintains the official registry of port number assignments.
Well-Known/System Ports (0-1023): The Well-Known or System Ports, ranging from 0 to 1023, are reserved for common, widely used services. These are only used by system processes, operating systems and default applications. These common network ports include HTTP (80), HTTPS (443), SMTP (25), and SSH (22).
Registered Ports (1024-49151): Thees ports are used by applications or services that are less common but still require specific ports to function properly.Important port numbers in this range include Remote Desktop Protocol (3389), Xbox LIVE and Games for Windows (3074) and IBM Lotus Notes/Domino (1352).
Dynamic/Private Ports (49152-65535): These ports are used for temporary or short-lived connections and are not assigned to specific services. They're often employed as source ports for outgoing connections and can be used by any process.
TCP UDP are two different protocols that use ports to manage network communications. The main difference between them lies in how they handle data transmission. Think of the options for sending a letter. TCP is like sending a registered letter that requires confirmation of receipt and to ensure ordered delivery. UDP, on the other hand, is akin to dropping a letter in a mailbox. While it may be cheaper and faster, it offers no guarantee of delivery or order. TCP prioritizes reliability, while UDP favors speed and efficiency.
TCP, or Transmission Control Protocol, is connection oriented. This means it establishes a connection before sending data and ensures that all packets arrive in the correct order and without errors. This makes TCP reliable but can slow down the communication process. It is commonly used for applications where accuracy is crucial, such as web browsing, email, and file transfers.
UDP, or User Datagram Protocol, is connectionless and does not establish a connection before sending data. It sends packets without checking if they arrive correctly or in order, which makes UDP faster and more efficient. This speed is beneficial for real-time applications like online gaming, video streaming, and voice calls where timely delivery is more important than perfect accuracy.
TCP (Transmission Control Protocol) ports are best used when:
UDP (User Datagram Protocol) ports are preferable when:
TCP is generally used for applications requiring reliable, ordered data transmission. The most common TCP ports include:
UDP is preferred for applications prioritizing speed and low latency over perfect reliability. Common UDP ports include:
Below is a list of the 15 most common ports and protocols in numerical order showing which protocol they use.
Think of how you contact the people you communicate the most on your cell phone. You connect to them by the contact's name in your phone, not thinking about the phone number that is assigned to them. All the common things you do on your computer such as web browsing or sending an email use ports behind the scenes as well. These ports act like invisible channels, directing different types of internet traffic to the right applications. Just as you don't need to remember phone numbers, you don't have to think about common port numbers when using the internet. The system automatically uses the appropriate ports for each service, ensuring smooth communication between your computer and various online services.
We all spend most of our time on the internet when on our computing devices. You open a web browser and begin to surf the internet using HTTP on port 80. You begin to shop for an item and use the HTTPS protocol to secure the purchase transaction using port 443. You then send an email to a friend using SMTP on port 25. You then transfer a file to a local server on your corporate network using FTP on port 21. Each of these actions were performed on a dedicated channel or port.
Both HTTP and HTTPS are used for web traffic. Unlike HTTP that sends data in plain text, HTTPS ensures that sensitive information like passwords, credit card details, and personal data remains confidential. This encryption ensures privacy and data integrity. HTTPS provides authentication through digital certificates. When a user connects to a website via Port 443, the server presents its SSL/TLS certificate. This certificate, issued by a trusted Certificate Authority, verifies the website's identity, helping users confirm they're connecting to the legitimate site and not a malicious impersonator.
Network managers have a vast IT estate that they must monitor and manage to keep their networks optimized and secure. Some of the common ports they use every day include:
Some ports are more secure than others, but no port is completely safe from compromise. Here are some of the potential security risks for popular ports you use every day.
At the very least, your network should be protected by a perimeter firewall. By default, a firewall closes ports for all incoming traffic and opens all ports for outgoing traffic. Every time a port is opened on the firewall it creates a potential entry point for attackers, thus increasing the attack surface of your network. Open ports can also reveal valuable information about the network infrastructure and services, aiding attackers in reconnaissance effort. Outgoing common open ports can be exploited for data exfiltration or to send malicious emails. Open ports aren't just an issue for perimeter security, however. Open ports on your local servers can enable lateral movement for attackers and facilitate the spread of malware.
Below is a list of security initiatives you should take to secure port traffic in your network.
While every network utilizes many of the well-known system ports, the registered ports used will vary according to the applications deployed by your organization. More examples of commonly used registered ports include:
Dynamic ports fall within a range of 49152-65535 and are typically used on the client side of a connection. In some cases, the dynamic port range can be configured to meet specific network requirements. These ports can either be specifically assigned by an operating system or can be randomized within the dynamic range. Dynamic ports are assigned temporarily and are released back to the pool when the connection is closed.
A classic example of dynamic ports in use is Network Address Translation (NAT). Workstations in a large organization are routed out the firewall to the internet. As outgoing packets pass through the firewall or NAT device, it changes the source IP address from the private IP to a public IP. Of course, there are not enough public IP addresses for each device to have a unique address. This is where dynamic ports come into play. The source is assigned a dynamic port, with each outgoing request receiving a different port number. All ports are stored in a NAT table to consistently translate packets from the same internal host and port to the same external IP and port. This is how return traffic is matched with the source devices.
Common applications that utilize dynamic ports include the following:
By default, a perimeter firewall blocks all incoming traffic from the Internet. If your organization hosts web facing applications, websites, email servers or data transfer sites, you will need to utilize port forwarding. Port forwarding allows specific incoming traffic to reach internal devices by mapping external ports on the router's public IP address to a specific internal IP address and port. When incoming traffic arrives on the specified external port, the router forwards it to the designated internal device.
Port scanning allows administrators and security professionals to gain a comprehensive understanding of their network infrastructure by identifying open ports, active services, and potential vulnerabilities. Regular port scanning can help ensure compliance with various security standards and regulations. Beyond security, port scanning aids in network troubleshooting, performance optimization, and change management by providing a clear picture of the network's current state. Some port scanning tools include Nmap, Netcat, and Angry IP Scanner. One of the most basic TCP Connect Scanning techniques involves attempting to complete a full TCP three-way handshake with the target system. Another simple way is to simply send UDP packets to detect open UDP ports.
Your applications, workloads and users all depend on ports to operate correctly. While an application or service needs an open port to operate, an open port also creates a vulnerability that a threat actor can exploit. This is why a proper understanding of ports is so important for network management and security. Familiarity with the ports assigned to commonly used services and applications can aid in troubleshooting and maintaining a robust security posture. By balancing the need for accessibility with prudent security measures, network administrators can ensure optimal performance while minimizing potential risks to their infrastructure.
What are the most common ports?
Whether you are an IT professional, an executive power user, or a personal computer user, these ports will be essential for your daily activities.
What is the most common port found?
The web is the most widely used application for users today, primarily relying on HTTP (Port 80) and HTTPS (Port 443) for communication. HTTP is the standard protocol for unencrypted web traffic, while HTTPS serves as the secure version, encrypting data to protect it during transmission.
What is the TCP port 444?
SNPP runs over TCP port 444 and allows pagers to receive messages via the Internet.
What are common ports 135?
TCP port 135 is primarily used for the RPC (Remote Procedure Call) Endpoint Mapper service. This port helps computers recognize and locate available services on other machines within the network, facilitating remote access and management in Windows systems
What are commonly used port numbers?
Commonly used port numbers include 21 (FTP), 22 (SSH), 25 SMTP), 67 (DHCP), (HTTP) 80, (POP) 110, (NTP) 123, 443 (HTTPS) and (RDP) 3389.
What are standard port numbers?
Standard port numbers, also known as well-known ports, are typically in the range of 0 to 1023. These ports are assigned by the Internet Assigned Numbers Authority (IANA) for specific services and protocols.
What are the 3 types of port numbers?
There are three main types of port numbers:
Is port 443 TCP or UDP?
HTTPS uses the Transmission Control Protocol (TCP) for HTTPS traffic on port 443. Web traffic requires TCP to ensure the reliable, orderly delivery of data. HTTPS provides secure web communications for users.
What are the most used ports in networking?
While most networks rely on numerous ports, the most common ports used in a networking environment: