It is very important to know the ports that are open on your computer, aka: What Ports Are Open, because some ports are associated with special services and these ports have to be open for your computer to run properly.
Apart from the ports that are used for special services, all other ports should be closed because the more open ports you have on your system, the more vulnerable it will be to hacking.
This is because ports are the doors through which access to your computer can be gained. Firewalls are the only locks that prevent access. Knowing the ports that are open is a step towards safeguarding your computer.
The special ports that should be open and their uses have been outlined below. Apart from these ports, all other ones should be closed.
Port 7: This port is also referred to as Ping and Echo. It is used to retrieve the IP address of your computer and its gateway. This is done by typing ipconfig in the command prompt. It is also used for troubleshooting. This is done by typing ping and the number of your gateway. You will get a response after.
Port 21: This is known as the FTP. This is used to either upload or download files to or from a server when websites are being updated.
Port 25: This port is called SMTP. It works with applications like Thunderbird, Pegasus and the popular Microsoft Outlook to send emails. Gmail, Yahoomail and Hotmail do not need this port because they are webmail.
Port 110: This port is called POP3 and it works with the same applications as Port 25 above to receive emails. It does not also work with webmail.
Port 53: This port is also known as DNS. This port helps to convert URL to the IP address of the website. Here is how it works. The computer does not understand the website you type on your web browser and you cannot cram the IP address of websites. So when you type the website, it is converted to the appropriate IP address for your computer through the process known as DNS. The computer now loads the page based on the IP address. Without DNS, you will have to be typing IP address and not the website. Imagine how difficult it will be.
Port 80: This port is known as HTTP. This is the route through which your computer gains access into the internet or to other websites. If this port is closed, you won’t be able to visit other websites.
Port 443: This port is known as HTTPS, it does the same thing as Port 80 but for secure websites.
Ports 135 to 139: This is known as NetBios. This gives you the name of any computer on your network.
In conclusion, the ports outlined above should be open on all computers and they are usually open by default if not tampered with. For the security of your computer, all other ports should be closed.