Understanding Ports: Functions, Types, and How Ports Work
Techy Mind
---
What are the types of ports that are often used in computer networks, what are ports, what are the functions of ports, and how do ports work?
We often hear the named port in a computer network, even more so maybe if you study networking then you are already familiar with this port. However, maybe you don't know everything about this port in depth. Usually, when studying the network we are only told to know the number of the port, for example, 23 for the telnet port and 443 for HTTPS.
What is a port in a computer network and what does it do?
A network port is a special process or application-specific software construct that serves as a communication endpoint, used by Transport Layer (OSI Layer 4) protocols of Internet Protocol packets, such as User Diagram Protocol (UDP) and Transmission Control Protocol (TCP). The port number is a 16-bit unsigned integer that ranges from 0 to 65535.
In its classification, the port is divided into two parts, namely Physical Port and Logical Port. The following is the definition of Physical port and Logical port:
A physical port is a physical network port that allows cables to be connected to computers, routers, modems, and other peripheral devices. Several types of physical ports are available on computer network hardware. A physical port, as opposed to a virtual or logical port, is an interface on a computer, where you can insert connectors for devices.
Examples of Physical Ports: RJ45 Port (Ethernet / LAN / NIC Port), Serial Port (RS-232), USB Port.
A logical port is a port used for file system service operations, based on an Ethernet port, bond port, or VLAN. Simply put, this logic port means that it is not physically visible but is still recognized as being like software on a computer. An example of a logical port is the port that you often know today, namely port 22 (SSH), 443 (HTTPS), 53 (DNS), etc.
 |
| Understanding Ports: Functions, Types, and How Ports Work |
The number range on the port is divided into two more types: some are registered with the Internet Assigned Numbers Authority (IANA) and others are not.
- 0 to 1023 – recognized port or system port.
- 1024 to 49151 – registered ports assigned by IANA to a more specific service upon request entity to an application.
- 49152 to 65535 – dynamic (private) ports range from 49,152 to 65,535. Can be used by private services or special services, so you can modify the function of the port.
An important part that is often used in computer networks
You also have to at least know the various ports that are often used in the network, especially for a network administrator, this is to make it easier for you to recognize the services that operate in it, especially in the field of network security.
Here are the ports that have an important role in a computer network:
1. Ports 20 & 21 (FTP)
FTP stands for “File Transfer Protocol”. The purpose of FTP is to transfer files over the internet. It sets out all the rules to be followed during data transfer. However, due to security concerns, FTP also requests user authentication before transferring data.
Port 20 serves to forward and transfer data. This port takes over the task of transferring FTP data when it is in active mode.
Port 21 is for signaling for FTP. It executes all commands and has flow control for data, which means port 21 is more flexible in transferring data because it has full control compared to port 20.
2. Port 22 (SSH)
SSH is also referred to as “Secure Shell”. This port is used to perform tasks that can be accessed remotely, such as connecting to a server or host. It also allows you to run many commands and move your files remotely as well.
This port transmits data over the network in encrypted form, in addition, only a person with access can remotely log in to the destination system using Port 22 to ensure that no information gets into unauthorized hands.
This port operates at the Application Layer (OSI Layer 7) TCP/IP model and is considered one of the most secure and reliable ports for remotely accessing files.
3. Port 23 (TELNET)
Port 23 (TELNET) is used to establish a connection between the server and the remote computer. The actual function is still the same as SSH, only the difference is in terms of security. This is because port 23 does not use encryption in its connection, causing telnet to become one of the less secure services to use.
4. Port 25 (SMTP)
SMTP stands for Simple Mail Transfer Protocol. The function of port 25 is to ensure that email messages are communicated over the network securely. This port is still at the Application Layer (OSI Layer 7).
This protocol not only performs the task of sending messages within the network but can send messages between various other networks. This makes it one of the most important ports for message communication over the network because of its security.
However, you do not have the right to download the email to be able to read it, as this is only to transfer it over the network.
Read also: What are Servers? Meaning and Types
5. Port 2525 (SMTP Alternative)
Port 2525 still has the same function as port 25: sending e-mail messages in a secure network. This port is used as an alternative port to port 25.
6. Port 53 (DNS)
DNS, also known as the "Domain Name System", serves to translate the IP address of each host from numbers to letters. If you visit a website with a name, for example techymind.in, actually behind the name has an IP address.
It's just that if we use IP addresses, then it's quite complicated. Therefore, computer scientists invented the idea of changing IP addresses to letters to make them easier to recognize and remember.
7. Ports 67 & 68 (DHCP)
DHCP is also known as “Dynamic Host Configuration Protocol”, this port runs on UDP protocol. Ports 67 and 68 serve to automatically assign IP Address related information to clients on the network. This information can consist of the subnet mask, IP Address, etc.
UDP port 67 performs the task of receiving address requests from DHCP and sending data to the server. On the other hand, UDP Port 68 performs the task of responding to all DHCP requests and passing data to clients.
8. Port 80 (HTTP / Webserver)
HTTP stands for Hypertext Transfer Protocol. The function of port 80 is to allow the browser/browser to connect to web pages on the internet. Port 80 is waiting for the web client to request a connection.
After a successful connection is established, you will be connected to the World Wide Web (WWW) and gain access to various web pages on the internet.
The alternative ports of HTTP / webserver are ports 8080 and 81.
9. Port 443 (HTTPS)
HTTPS port 443 serves to connect you to the internet by establishing a connection between a web page and a browser connected to the World Wide Web (WWW). However, this port has additional security features, which HTTP port 80 does not have.
This port is created to create a more secure connection to ensure that data is transmitted over a secure network. This port encrypts and authenticates network packets before transferring them over the network for increased security. This security feature was introduced by the use of SSL, which can also be referred to as Secure Socket Layer.
10. Port 110 (POP-3)
POP3 is also referred to as Post Office Protocol Version 3 which operates on port 110 of the TCP Protocol. This port 110 allows email messages to be retrieved from the SMTP server. Using this port, you can download messages from the server and then read them. In addition, messages will also be deleted from the server once downloaded.
However, this port has security issues. Authentication transferred over the network is not encrypted and is sent in plain text. This allows hackers to get the information in it and misuse the information easily.
11. Port 119 (NNTP Server)
NNTP Server or known as Network News Transfer Protocol uses port 119. This port serves to accommodate servers from the world of USENET newsgroups (news).
12. Port 143 (IMAP)
IMAP stands for "Internet Message Access Protocol". IMAP port -143 serves to retrieve email from a remote server without having to download email. This means that you have the freedom to access your email from anywhere as long as you are connected to a server.
However, you can also download e-mails if you wish. It also gives you the convenience of searching for your messages from the many existing messages. In addition, this port also ensures that data remains secure throughout the connection.
13. Port 389 (LDAP)
LDAP stands for “Lightweight Directory Access Protocol” using port 389. Port 389 serves to handle authentication requests from client computers that aim to provide access to directories, telephones, addresses, etc.
14. Port 3389 (RDP)
TCP port 3389 is used for Windows Remote Desktop Protocol (RDP) and is also occasionally used by Windows Terminal Server. This port is often used by hackers to carry out Distributed Denial of Service Attacks or better known as DDOS.
15. Port 445 (SMB)
Port 445 is used for Server Message Block (SMB). SMB serves Windows File and Printer sharing ( file sharing ). In Windows 2000, Microsoft created a new transport for SMB over TCP and UDP on port 445, which replaces the older implementation over ports 137, 138, and 139.
16. Ports 1503 & 1720
Ports 1503 and 1720 are used by collaborative multimedia applications such as NetMeeting to establish and control collaborative sessions. In addition, an example is VOIP (Voice Over Internet Protocol) which functions to make calls over the internet such as Voice Call on WhatsApp.
17. Port 3306 (MySQL)
Port 3306 is the default port for the MySQL Protocol, which is used by the MySQL client, MySQL Connector, and utilities such as mysqldump. Port 33060 is the default port for the Database Extended Interface (MySQL X Protocol).
18. Port 5631
Port 5631 is the default port on computer networks that serves to connect computer networks with pcAnywhere. pcAnywhere is an application created by a networking company called Symantec to provide remote control functionality. Not much different from SSH and telnet, only pcAnywhere is in the form of graphics / GUI.
19. Port 5900 (VNC)
VNC stands for “Virtual Network Computing” using port 5900 in its service. This port runs desktop sharing applications and independent remote control platforms. VNC is very popular and is used for remote support in many large organizations. The way it works is not much different from pcAnywhere.
20. Ports 8080 & 3128 (Proxy)
In addition to HTTP, Proxies also use the same port as HTTP because they are still running on the same service but have different functions. In addition to port 8080, there is also an alternative port for the proxy, namely port 3128.
Read also: 12 Common Beginner Blogger Mistakes
Thank you for visiting, I hope you are now more aware of the important ports that move in computer networks. May be useful…
Post a Comment
Post a Comment