Common Network Ports and Protocols: A Simple Guide for Beginners

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Network ports and protocols are the reason your computer can browse a website, send an email, and join a video call at the same time. A protocol is a set of rules for communication. A port is a numbered door that tells the data which application it belongs to.

In this guide, you will learn what ports and protocols are, which common ports every beginner should know, and how to check them on Windows.

Network Ports and Protocols in One Minute

• Protocol: The rules devices follow to talk to each other, such as HTTP, DNS, or SSH.
• Port: A number (0 to 65535) that identifies a specific service on a device.
• Together: The IP address finds the device, and the port finds the application on that device.

What Is a Network Protocol?

A protocol is a common language. Both devices must follow the same rules, or they cannot understand each other.

For example, HTTPS defines how your browser and a website exchange data securely. DNS defines how a name like baytenet.com is turned into an IP address.

What Is a Network Port?

A port is a logical number, not a physical connector. It lets one device run many services at the same time.

Think of an IP address as the address of a building, and a port as the apartment number. The address gets you to the building, and the number gets you to the right door.

You often see them together, like this: 192.168.1.10:443. The part before the colon is the IP address, and the part after it is the port.

How Ports Work with TCP and UDP

Every port is used with a transport protocol, either TCP or UDP. Some services use one, and some use both. If you are not sure about the difference, read our guide on TCP vs UDP: Key Differences Explained for Beginners.

The Three Port Ranges

Range	Name	Used for
0–1023	Well-known	Standard services
1024–49151	Registered	Applications
49152–65535	Dynamic	Temporary use

When your browser connects to a website, it uses port 443 on the server and a temporary dynamic port on your own device.

Common Ports You Should Know

Web

Port	Protocol	Transport
80	HTTP	TCP
443	HTTPS	TCP, UDP

HTTPS on port 443 usually runs over TCP. HTTP/3 uses QUIC over UDP, also on port 443.

Remote Access

Port	Protocol	Transport
22	SSH	TCP
23	Telnet	TCP
3389	RDP	TCP

File Transfer

Port	Protocol	Transport
20, 21	FTP	TCP
69	TFTP	UDP
445	SMB	TCP

Email

Port	Protocol	Transport
25	SMTP	TCP
110	POP3	TCP
143	IMAP	TCP

Network Services

Port	Protocol	Transport
53	DNS	UDP, TCP
67, 68	DHCP	UDP
123	NTP	UDP
161	SNMP	UDP
514	Syslog	UDP

Secure vs. Insecure Protocols

Some older protocols send data as plain text. Attackers can read it if they capture the traffic. Each one has a secure replacement.

Insecure	Secure
HTTP (80)	HTTPS (443)
Telnet (23)	SSH (22)
FTP (21)	SFTP (22)
POP3 (110)	POP3S (995)
IMAP (143)	IMAPS (993)

Tip: In real networks, always use the secure version when you can.

How to Check Ports on Windows

To see which ports are in use on your computer, open Command Prompt and run:

netstat -ano

The output shows the protocol, local address and port, remote address and port, state, and the process ID (PID).

To check if a specific port on another device is reachable, open PowerShell and run:

Test-NetConnection google.com -Port 443

If the result shows TcpTestSucceeded : True, the port is open and reachable.

Why Ports Matter in Networking

• Firewalls: Rules allow or block traffic by port number. If port 443 is blocked, websites will not load.
• Troubleshooting: If an app cannot connect, the port may be blocked or the service may not be running.
• Security: Open ports you do not need make your device an easier target.
• CCNA exam: You are expected to know the common port numbers and their protocols.

Frequently Asked Questions

Is a network port a physical connection?

No. A network port in this article is a logical number in software. It is different from the physical port on a switch or router, such as an Ethernet port.

How many ports are there?

There are 65,536 ports, numbered 0 to 65535. TCP and UDP each have their own set of port numbers.

Can I change a default port?

Yes. For example, you can run SSH on a port other than 22. Both sides must use the same port, and firewall rules must allow it.

Which ports should I memorize for the CCNA?

Start with these: 20/21 (FTP), 22 (SSH), 23 (Telnet), 25 (SMTP), 53 (DNS), 67/68 (DHCP), 69 (TFTP), 80 (HTTP), 110 (POP3), 143 (IMAP), 161 (SNMP), and 443 (HTTPS).

Conclusion

Protocols define the rules, and ports decide which service receives the data. Once you know the common ports, firewall rules, troubleshooting, and security become much easier to understand.

To see where this fits in the bigger picture, read our guide on OSI Model vs. TCP/IP Model.

Leave a comment if you have any questions!