What is port 80 and what does it eat?

When configuring a network or installing a home server, you might come across a concept such as port 80. Normally, you first need to check for access to it. Port 80 is most often closed. In order to better understand what it is, it is necessary to outline the principle of the Internet.

Principle of operation

How does access to information via the Internet occur? We have a user who wants to connect to the site. It includes the Internet and starts the browser. This is the same client program. It is installed on the user's computer. In the address bar of the Internet browser, he enters the name of the site. This is his domain name. Then what happens is usually hidden from our eyes. Between the input of the site address and its response, the following occurs. Entering the domain name into the browser, we contact the provider. We inform him that he wants to request this site. The provider has a DNS server (Domain Name Server), which converts the site name to an IP address.

For example, 178.200.144.124. IP is an internetwork protocol. It is issued by the provider of the computer every time you connect to the Internet. If the IP address is dynamic, then it can change at the discretion of the provider. If the IP address is static, then it does not change. This is necessary in those cases when you want to configure security settings for something and set access only from certain IP.

It is clear that computers also have their own IP-addresses. Now there are two versions: IPv4 and IPv6. They are needed to find a computer on the network. You need to know where to send the packet of information. Further, the provider forwards the site request to the router. According to the route tables, it sends the data to the specified address.

Further on the web server there is a processing of the received information and the result is produced in the form of an HTML page. It goes through the reverse chain, passing the router, to the provider, and from there - to the client's computer. Here it is necessary to understand where to send the package to which program. For this, we need ports.

What occupies port 80

First of all, you need to understand what it is. A port is a specific system resource that is allocated to an application to communicate with other programs on the network. They use ports for communication among themselves through the network. Comparing this design with the house, we can say that IP is a house, and a port is an apartment. A total of 65,536. Some of them are reserved for work with only certain applications. The list of ports is in the services file in the C / Windows / System32 / drivers / etc directory. But it can differ, depending on the version of the operating system.

Web sites also require port 80. To test its operation, you can do the following. After the site name, put a colon and enter the port number. For example, port 80. You will open the site. If you enter a number, for example, 53, you will get a message telling us that this address is using a port that, as a rule, is not used for working with websites. But usually we do not specify it in the address bar. This is done by the browser itself. Port 80 is in it by default.

Testing the connection

All applications that use web resources for their work use this port to communicate over the Internet. Even if you do not work in the browser at the moment, it can still be used, for example, by an antivirus. Check which connections are currently installed through it, you can at the command line. After pressing the Windows + R keys, enter the cmd field and click OK. In the command window that opens, type netstat-an. The program will output the results of connections that were installed by our computer with remote nodes. The so-called devices are included in the architecture of the computer network.

In the column "External address" you can find all the web resources that currently use the eightieth port. With this method it is convenient to track malicious software and unnecessary connections. But it happens that for the operation of completely innocuous programs it is necessary to open port 80 manually.

How to check 80 port?

If you have encountered programs such as skype and law, you probably know that they configure and open the necessary ports in automatic mode using UPNP technology. Also they add themselves to the list of exceptions of most firewalls and antiviruses. When configuring a game or web server, you need to do this manually. Before doing this, the port needs to be checked. You can do this in several ways.

Network resource

Some people like to use the service 2ip.ru. There is a useful "Check Port" function. If you come here and enter the number we need, the site will tell if the port is closed or not. But you need to understand that checking through this site may not always be correct. In order for it to pass as correctly as possible, it is necessary to run the program for which this check is required. Also she should listen to this server. For more accurate verification, you can use the following method.

Software resource

Install the program PFPortChecker. At installation it is better to refuse advertising links. The peculiarity of this program is that it itself listens to the port, which we want to check - it is open or closed. At the top you must specify the port number, the connection protocol and click Check Me. The connection protocol is either TCP or UDP. Choose TCP. If the program reports that the port is closed, you need to make sure it is blocked by the firewall. If your antivirus does not have a firewall function, then it activates the functions of the built-in Windows screen. For the duration of the test, you must disable it, it is done through the control panel. Now, repeat the operation with PortChecker. If it shows that the ports are still closed, you can conclude that they are blocked on the router. This means that you need to configure the router itself. How to do this, it is difficult to say here, because each router has its own settings.

You need to go into its management interface and prescribe the settings for port 80.
So, you learned what port 80 is, how to test it and what to do in order to set it up.