How can I check if the port is open on a remote computer or server? Yes, and this is relatively easy to do. Any person who does not even have a significant amount of knowledge and skills can cope with a computer. Let's get started.
Local computer
In this case, it is very easy to check if the port is open. To do this, call the command line. Use the keyboard shortcut Win + R for this purpose. After the window opens, you need to register the cmd command and press the enter key. As a result, we have the command line. In the window that opens, you need to register netstat -a. After that, a list of ports that are currently open will be displayed.
Remote computer
The same command line is used for this purpose. Only now it is necessary to introduce three elements: "telnet - IP address - port". Press the enter key. If the entry “Could not open” does not appear, then it means that it is open. In cases when it is displayed, the port is closed. If there is no time to break through all the values, but at the same time it is necessary to check whether the port is open, then for this purpose you can use utilities. By the way, the telnet command allows you to consider the local computer as remote, working with it in such a way that it is difficult to be at a distance. What is the mechanism of such work? In this case, the command line entry looks like "telnet - localhost - port".
Server
In this case, checking if the port is open is the most difficult. Since the author proceeds from the fact that readers will not engage in hacking equipment and have administrator rights, the corresponding behavior will be considered. Initially, it is necessary to ensure the operation of the service, which will work on a specific port. For this purpose, you can use the netcat utility, thanks to which you can listen to his work. It allows you to use the TCP and UDP protocols, receiving and transmitting data. Speaking about its advantages, it is necessary to note a fairly wide range of features, clear guidance and ease of use.
By the way, to work with servers, you can use the telnet command discussed earlier, the only question is the convenience of working with it. After all, you may need to conduct a mass port check. For if you sort through everything manually, it will take too much time. In this case, no options - you must use utilities. Without them, a mass check to see if the port is open, although it is possible, will entail a loss of time. At the same time, the work is not complicated. You just need to add a specific host (as an option - the IP range), indicate what is the object of research, and start the procedure. True, in this case there is a negative point: such actions are considered by many defense systems as a DDOS attack, which entails a ban.