How can I check if port is open? - Open Port

How can I check if port is open?

To make it fast, if you need to check if port is open on your windows device without downloading or installing any tool, just open the command line and type ‘netstat -an’ to get the list of the currents open ports, more information on the netstat command line can be found on our site under netstat.

check if port is open

open port checker

What is open port?

The first question that once can ask himself in related to is my port open is what is a port? we are talking a lot in here about ports, open ports etc.
so, what is a port, in related to networking?
A port is an entrance like a door or a window.

So why is it open?

It is open so that data can be transmit in and out of the device using that port – door, the first example that I am talk about is the one that we all use on a daily basis, websites.

when you open your browser and type in the site you want to see there are some things that happens behind the scene that you may not know about.

There is a default port that web servers using so that you and others can communicate with, so the HTTP protocol use a default port of 80 for its initial communication and the HTTPS protocol use the default port 443 for its initial communication, why initial, due to the fact that it need to serve a lot of connection on the same time and be able to send each one it relevant data, how, after the initialization connection it generate a random port – open another port, and send receive all the data using that port.

If you think about it, every software that use the internet or even the inner LAN – Local Area Network (like the devices that connected to your home router, or all the devices that connected in an office), must open a port to send and receive data over the network, and each tool use its own port.

Type of open port protocols:

There are 2 main protocols that are in use when we talk about networking, the TCP – Transmission Control Protocol and UDP – User Datagram Protocol what is the main diff between them you ask, well, in UDP the data may arrived not in the order that you expected it to arrive so it also call an unreliable protocol.

RE: send and forget the data, TCP on the other hand is a reliable protocol that check and verify every package you send.

In networking, there are some protocols that can be used to open port as we explain the port can be open for TCP connection and /or for UDP connections so in term of port checkers we need a TCP port checker and/or a UDP port checker of course we can use one port checker that implement both of them.

Port Checker – Port Scanner, what?

As mention already we need to be able to use a port checker or it will be more accurate to say an open port checker to check the state of a target port, open or close, to do that there are useful tools that are more like an open port scanner, you give them a target and they can scan a list of port or all the port on that target, there are also online port scanner which are web sites that run a script to check the status of ports on a target host, IP or device.

Wait, you say IP!?

An IP address in a simple word is you online address, IP stand for Internet Protocol and it is the address that above it you can check if a port is open or not, this is why some of the port scanners can also run on more than one IP as an IP checker to find all the open ports on a dedicated IP and continue to check IP after IP till it check all the IPs in the target list of IPs, or network mask.

OK, now what is network mask?

Oh, and network mask, or subnetwork AKA subnet is a logical subdivision of an IP network can be use to distinct between network into two or more sub networks in an environment, let’s say we have 100 servers, some are windows and some are Linux, so all the windows will be in a subnetwork and all the Linux will be in another subnetwork, this will make it very easy to know by the IP address what is the host operation system – Window or Linux as an example.

Tool to check if port is open:

If you want to check some nice tools that can determinate if a port is open, open google and type in nmap or Advanced IP Scanner, by the way our pingui tool can also be used to check if port is open on your local windows device, you can download it for free and try it.

In Conclusion:

The fast and easy way to check if port is open is using the build in netstat command line tool or search for one of the tools mention on this article and use them to do it, another option is to use an online port checker like our front page. 


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