well known port numbers list

Common Ports Cheat Sheet: The Ultimate List

Perhaps you’re angsty that you’ve forgotten what a certain port number meant. Rest assured, you don’t have to remember all 65,535 port numbers. With so much information to remember, it’s understandable if you forget a common port. That’s why we put together this cheat sheet of common network ports for you.

A crucial domain of expertise in IT-related certifications such as Cisco Certified Network Associate (CCNA) and those of CompTIA is port numbers and associated services , which this common ports and protocols cheat sheet covers. If you want to remember a port number or protocol, this cheat sheet will help everyone, from students to professionals.

Get a copy of this common ports cheat sheet here to keep on your desk. When you're ready, scroll below to find the port you’re looking for.

Common Ports Cheat Sheet Search

Search our Common Ports cheat sheet to find the right cheat for the term you're looking for. Simply enter the term in the search bar and you'll receive the matching cheats available.

Common Ports and Protocols Cheat Sheet

The following tables cover services (and malware) that use common TCP ports and some UDP or SCTP ports.

Well-known/System Ports: 0 – 1023

Registered Ports: 1024 – 49151

Dynamic/Private Ports: 49152 – 65535

You may use these ports for custom applications free from concerns that it may clash with existing processes.

The Most Common Ports for Exams

If you’re studying for IT certifications such as CCNA , focus on these ports:

We hope that you found this cheat sheet useful. Familiarity with ports and protocols is vital to building secure applications and troubleshooting problems on computer networks. Whether you're studying or working, this cheat sheet of common network ports will help you in academic and professional settings.

For further resources, or if you’re curious about how ports and protocols fit into cyber security, look into network security courses available with our StationX Accelerator Program .

Frequently Asked Questions

FTP: ports 20-21; SSH/SCP: port 22; HTTP: 80; HTTPS: 443; POP3: 110; POP3 over SSL: 995; IMAP: 143; IMAP over SSL: 993. We recommend you download the graphic in Well-known/System Ports .

It depends on whether you’re referring to system ports (1024) or want to include ports registered with apps (49152) because system ports range from 0 through 1023, and registered ports span 1024 – 49151.

FTP: ports 20-21; SSH/SCP: port 22; Telnet: 23; SMTP: 25; DNS: 53; HTTP: 80; POP3: 110; IMAP: 143; HTTPS: 443.

FTP: port 21; SSH/SCP: 22; Telnet: 23; SMTP: 25; DNS: 53; POP3: 110; IMAP: 145; HTTP: 80; HTTPS: 443; MySQL: 3306; RDP: 3389; VNC: 5900.

The following are the three types of ports with corresponding port number ranges: • Well-known/System ports: 0 – 1023 • Registered ports: 1024 – 49151 • Dynamic/Private ports: 49152 – 65535

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Nathan House is the founder and CEO of StationX. He has over 25 years of experience in cyber security, where he has advised some of the largest companies in the world. Nathan is the author of the popular "The Complete Cyber Security Course", which has been taken by over half a million students in 195 countries. He is the winner of the AI "Cyber Security Educator of the Year 2020" award and finalist for Influencer of the year 2022.

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Nathan, thank you for supplying this sheet. It comes in handy when you’re trying to remember what a particular port is used by.

Our pleasure.

Thank you, Nathan

This is a great single point to reference all default ports. Thank you!!!

Very good, it will be in front of me!

Ports on computers are required for networking, and without them, the computer would be completely isolated and it would be unable to communicate with other devices. So thank you for proving this list of the Common TCP and UDP Port numbers.

After resetting my router cause the password got changed and all the setting were changed to gain access to my computer. I spent about 20 minutes setting up the router. It appears the router never got set up from the cable company when it was installed. So if you have not done so lately check your router and settings.

Cool, Thanks for sharing!!

Sorry Nathan, i did not leave a comment for this “Common Ports” Chart last-week. I am glad i signed up to your news letter you are a good researcher. thank you for sharing with us all..

Nathan, I must thank you for these cheat sheets! They’ve been great on my learning and certification journey!

Thank you too!

Really really useful.Thanks a lot!!

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50 Common Ports You Should Know

Port number is a 16-bit numerical value that ranges from 0 to 65535. Well-known port (0-1023), registered port (1024-49151), and dynamic port is three types of port number space. (49152-65535).

These ports can be opened and used by software applications and operating system services to send and receive data over networks (LAN or WAN) that employ certain protocols (eg TCP, UDP).

For example, we use 80 for HTTP-web-based plain-text surfing and 443 for HTTPS-web-based encrypted websites in our daily work.

To conclude, a port is a logical form to identify system activities or various network services used to create local or network-based communications.

What are the functions of ports?

When interacting over the Internet, TCP and UDP protocols make connections, recompile data packages after the transfer, and then deliver them to applications on the recipient’s device. For this handover to work, the operating system must install and open the gateway for the transfer. Each door has a unique code number. After transmission, the receiving system uses the port number to determine where the data should be sent. The port numbers of the sender and receiver are always included in the data packet.

Ports are assigned sequential numbers from 0 to 65535. Some of these codes are standardized, meaning they are assigned to certain uses. Since code numbers are universally recognized and permanently assigned, these standard ports are also known as well-known ports. Registered ports are those that organizations or software developers have registered for their applications. Registration is handled by the Internet Assigned Numbers Authority (IANA). A diverse selection of dynamically assigned port numbers is also available. For example, when viewing websites, browsers use these ports. After that, the port number is free again.

Why is it important to know these ports?

Any security researcher, bug bounty hunter, or anyone working with service configuration would benefit from this. Knowing how to do more thorough scans such as version detection or known vulnerabilities for ancient services that are still operating in the infrastructure, especially when using tools like Nmap, is handy when getting to know these protocols and services. 

The most 50 significant ports are listed here:

The following are some of the most common service names, transport protocol names, and port numbers used to differentiate between specific services that employ TCP, UDP, DCCP, and SCTP.

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How many Well-Known TCP Port Numbers are there?

Port numbers 0 to 1024 are reserved for privileged services and designated as well-known ports. This list of port numbers are specified in RFC 1700.

List of Well-Known Ports

Port numbers range from 0 to 65535, but only port numbers 0 to 1023 are reserved for privileged services and designated as well-known ports. The following list of well-known port numbers specifies the port used by the server process as its contact port.

• Well-known ports range from 0 through 1023.
• Registered ports are 1024 to 49151.
• Dynamic ports (also called private ports) are 49152 to 65535.

For further information, see RFC 1700.

This article was last updated on November 02, 2017

Since 1995, more than 100 tech experts and researchers have kept Webopedia’s definitions, articles, and study guides up to date. For more information on current editorial staff, please visit our About page.

Common Ports Cheat Sheet

It’s a pain trying to memorize port numbers and their corresponding service names and protocols. So, we created this concise cheat sheet of common network ports and their associated protocols and service names for you to use as a quick reference.

Feel free to print it out and hang it up or share a link to it with your colleagues and peers. Use it to speed up port identification or as a training resource for onboarding new network administrators or engineers.

Free Common Port Cheat Sheet

Click on the network port chart above to view the printable, searchable PDF version. Scroll down below for the port list tables.

This list is by no means exhaustive. It just lists the most frequently used ports. There are a total of 65,535 TCP/UDP ports. They are divided into 3 classes:

• Well Known Ports (1-1023) – Reserved ports registered with IANA for specific services.
• Registered Ports (1024-49151) – Also registered with IANA but not as commonly used.
• Dynamic/Private Ports (49152-65535) – Reserved by IANA for proprietary services or private use.

IANA (Internet Assigned Numbers Authority), in case you’re wondering, is the organization that oversees global IP address allocation and port classification.

Some common protocols that use these ports:

• TCP (Transmission Control Protocol)
• UDP (User Datagram Protocol) – Only one port needed for bidirectional traffic
• SCTP (Stream Control Transmission Protocol)
• DCCP (Datagram Congestion Control Protocol)

Common Well-known/System Ports in Computer Networking

Well-known network ports range from 0 to 1023. These ports are assigned by IANA and listed in RFC 1700 . On most systems they can only be used by system (or root) processes or by programs executed by privileged users. Some well-known ports use TCP, some use UDP, and some can be configured to use either. 

Well-known TCP ports are used by applications that rely on TCP as the transport protocol. Examples:

• FTP (File Transport Protocol) uses TCP ports 20 and 21
• Telnet uses TCP port 23

Well-known UDP ports are used by applications relying on UDP. Examples:

• TFTP (Trivial File Transport Protocol) uses UDP port 69
• SNMP uses UDP port 161 for messages and UDP port 162 for traps

Knowledge of these ports is helpful for network engineers looking for work as they are popular topics asked about in technical interviews.

Common Registered Network Ports

Registered network ports are ports in the range of 1024 to 49151 that have been officially registered with the Internet Assigned Numbers Authority (IANA) for specific services and applications.

Some key points about registered ports:

• They come after well-known ports (0-1023) and before dynamic/private ports (49152-65535).
• Anyone can register a port in this range with IANA for their application/service.
• Registration ensures the port number is standardized and should not be used by other services.
• Examples include port 3306 for MySQL, port 1521 for Oracle database, port 1723 for PPTP.
• Not as commonly used as well-known ports, but still important for avoiding conflicts.
• Provide an official way to allocate ports for proprietary applications and organizational services.
• The full list of registered ports is maintained by IANA and published on their website.
• Helpful for network administration to know what traffic these registered ports are associated with.

Common Dynamic/Private Network Ports

Dynamic/Private network ports refer to the range of ports from 49152 to 65535 that are not officially registered with IANA for any specific service or application and are available for private or temporary use. 

They can be used by applications dynamically as needed, usually for establishing temporary connections. Often they are used by client-side applications that initiate connections to servers on well-known or registered ports. 

A common example of dynamic network port use is Ephemeral Ports. These are short-lived transport layer ports used when an application on a client device makes an outgoing connection to a server. They allow a client application to use a random available port for its side of the connection which has multiple benefits from enabling multiple connections from the same client application to traversing firewalls as most firewalls are configured by default to allow connections from ephemeral ports to well-known ports.

The dynamic/private port range also provides ports for private or customized services within an organization since they are unregistered.

Top 35 Most Common Ports for Certification Exams and Interviews

Prepping for an exam or interviewing for a role in networking or a networking adjacent field? Prioritize memorizing the ports below.

In my experience, these are the ports most frequently used in certification exams and to quiz candidates in technical interviews.

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Well-Known Port Numbers

Last Edited

Definition of Well-Known Port Numbers in Network Encyclopedia.

What is Well-known port numbers?

Well-known port numbers are port numbers for Transmission Control Protocol (TCP)  or User Datagram Protocol (UDP)  that have been assigned to specific TCP/IP applications or services by the Internet Assigned Numbers Authority (IANA) . Well-known port numbers are assigned within the range 0 through 1023 and are specified in Request for Comments (RFC) 1060. (The total range of possible port numbers is 0 through 65535.) The following table describes some of the well-known port numbers.

“Registered ports” are port numbers that are not controlled by IANA but that IANA registers to indicate to the Internet community which vendor applications use them. Registered ports range from 1024 through 65535 and can be used by any process or program requesting it if the operating system has not already allocated it for a specific use. Programs and processes that communicate using remote procedure calls (RPCs) often randomly select a registered port for each RPC communication session.

Port Number List

How Does Internet Work

Tcp and udp port numbers – complete list.

This is a list of Internet socket port numbers used by application communication with TCP and UDP on the Transport Layer of the Internet Protocol Suite for the host-to-host communications.

Let’s see who makes it possible? The Internet Assigned Numbers Authority (IANA) assigns all port numbers except Dynamic or Private ports. IANA is a standards organization in the world that is responsible for assigning various addressing standards.

There are different types of port numbers: Well Known Ports (Numbers 0 to 1023), Registered Ports (Numbers 1024 to 49151) and Dynamic or Private Ports (Numbers 49152 to 65535). The last porn number type  Dynamic or Private Ports  will not appear on our list because they are cannot be registered with IANA. This range is used for custom or temporary purposes and for automatic allocation of ephemeral ports. They are usually assigned dynamically to client applications when initiating a connection. It is not very common for a client to connect to a service using a Dynamic or Private Port, sometimes some peer-to-peer file sharing programs do.

We will introduce the list of the ports with short description of different port types.

Using both TCP and UDP is also normal sometime. Some applications may use both TCP and UDP. For example, the low overhead of UDP with his short header enables DNS to serve many client requests very quickly. However, sending the requested information sometimes may require the reliability of TCP. In that case, the port number of 53 that is a well known port number is used by both protocols with this service.

Let’s see the list of port numbers:

• Well-known ports
• Registered Ports

Well Known Ports (Numbers 0 to 1023) – These numbers are reserved for services and applications. They are commonly used for applications such as HTTP (web server) POP3/SMTP (e-mail server) and Telnet. By defining these well-known ports for server applications, client applications can be programmed to request a connection to that specific port and its associated service.

Registered Ports >> Registered Ports

Registered Ports (Numbers 1024 to 49151) – These port numbers are assigned to user processes or applications. These processes are primarily individual applications that a user has chosen to install rather than common applications that would receive a Well Known Port. When not used for a server resource, these ports may also be used dynamically selected by a client as its source port.