How to set up reception of connections via 8080 (port): instructions, diagram and reviews
A port in computer networks is a natural number that is written in the header of the OSI protocol. It is designed to identify the receiving process of a packet in a single host.
As a rule, several processes occur simultaneously in the user space on a host with an installed OS, and a specific program runs in each of them. If these programs affect the computer network, the "shell" from time to time receives an IP packet through it, which is intended for one of the programs.
How does it work?
If the program uses data exchange over the network, this process can occur as follows:
A specific port number is requested from the OS. In this case, the system can either provide it to the program or prohibit transmission (this happens if this port number is already used by another application).
An unspecified port number is requested from the OS, in any free one. The system selects it itself and provides it to the program.
How do I open the port (8080, 80 and so on)? Inside the network, information is exchanged according to a specific protocol (between two processes). In order for the connection to be established, the following is required:
IP addresses of the recipient and sender hosts (required for a route to be built between them);
Protocol number;
The numbers of both ports (receiver and sender).
If the connection is over TCP, then the sender's port is used both by the recipient's OS to transmit confirmation of the received data, and by the recipient's process to transmit a response.
Open and closed ports
On the sender's side, the host and port number act as an analogue of the return address, which is indicated on envelopes. This number is called the reverse.
In cases where a process on the host uses the same port number on a regular basis, such a port is considered open. For example, a program connected to a server can use 80 or 8080 for communication all the time. When a process cannot open a port, it is considered closed.
Port numbers
All ports have their own numbers registered in the prescribed manner. Each of them is designed for its own specific purpose. So, when working on the Internet, you can often see port 8080. Why do I need such functionality?
According to official data, this port operates over the TCP protocol and is intended for use with HTTP. Unofficially, it is also used by the Tomcat servlet container written in Java.
TCP port 8080 may use a specific protocol for communication, depending on the application. The protocol is a set of formalized rules that explains how data is transmitted over the network. This can be thought of as a language that is used between computers to help them communicate more efficiently.
The HTTP protocol, which works over 8080, defines the format of communication between Internet browsers and websites. Another example is the IMAP protocol, which defines the communication between IMAP mail servers and clients, or, finally, the SSL protocol, which specifies the format used for encrypted messages.
Data transmission
Thus, TCP port 8080 uses the transmission control protocol. It is one of the main protocols in TCP/IP networks. While the IP protocol deals only with packets, TCP allows two hosts to establish a connection and exchange data streams. It guarantees their delivery, as well as that the packages will be delivered to port 8080 in the same order in which they were sent. Guaranteed 8080 communication is the key difference between TCP and UDP. UDP 8080 would not guarantee a connection the same way.
How do I open port 8080 in Windows 7?
To do this, go to the Start menu and find the Control Panel. In it, you need to click on the "Network" submenu and find "Branmauer" in it. In the "Exceptions" tab, find the "Add port" item. A dialog box will open in which you will need to enter the port number. Make sure that TCP is specified in the settings, then select OK.
How do I close port 8080?
To do this, it is enough to configure the connection to another specific port.
Advanced HTTP and TCP proxy server configuration
The HTTP protocol works on top of the TCP protocol, but provides additional information about the purpose of the message. For this reason, the two proxies are configured differently.
HTTP traffic includes the target host and the port for the message. It is sent over a TCP connection to a TCP endpoint, that is, between a specific host and a port. Typically, an HTTP message points to the same endpoint as a TCP connection. If you change the client configuration to use an HTTP proxy server, the connection is made to a different host and port, instead of the one specified in the HTTP URLs. This means that the TCP endpoint in the message is different from the endpoint to which it is connected.
For example, if an HTTP request is sent to a page http://192.0.2.1:8080/operation , the request includes "192.0.2.1:8080" in the header of the "Host" HTTP message, which is sent to the 8080 port on the host 192.0.2.1.
However, if you configure the HTTP client to use a proxy server, the underlying TCP connection goes to the TCP endpoint for it, while the messages still contain the original endpoint.
For example, if you configure the client to send its messages to the proxy server at 198281.100.1 port 3128, and the client sends a request for http://192.0.2.1:8080/operation , the message still contains "192.0.2.1:8080" in the "Host" header, and now also in the "Request-Line" field. However, this message is now being sent over a TCP connection to 198.51.100.1:3128. Thus, an HTTP proxy server can receive messages on a single port (proxy port 8080) and can forward them to several different services based on recipient information.
How do I configure the reception of connections via port 8080?
So, the "Host" header was added to HTTP/1.1. HTTP/1.0 connections does not include it. For this reason, such connections that do not pass through a proxy do not include a host and a port for the message. However, the HTTP/1.0 information sent through the proxy server still contains the target host and port in the "request string". Therefore, the absence of the "Host" header does not cause problems for the proxy.
To enable a TCP proxy server, you must change the client configuration from a real-time TCP endpoint to a replaceable endpoint. Unlike HTTP, this protocol does not provide a built-in proxy capability. That is, if you connect to a proxy server via TCP, there is no mechanism for transmitting information to the final destination.
How to set up multiple connection using 8080?
The only way for a TCP proxy server to allow connections to multiple systems (that is, to destination endpoints), regardless of what traffic will be sent over these connections, is to listen on a different port for each of the systems. This allows you to connect and maintain information about which of its port numbers corresponds to each endpoint. The client is then configured with a proxy port corresponding to each system it needs to connect to. TCP proxy listening ports and their corresponding endpoints are configured in the statements in the proxy configuration file, RTCP_install_dir /httptcp / registration.xml . First of all, you need to check port 8080 – if it is open by default, further settings will be made in a few minutes.
In this example, 198.51.100.1 is the IP address of the proxy server. Any traffic sent to port 3333 to the proxy server is sent to port 8080 at: www. Example. com:
Therefore, you should change the client configuration file whenever you add a new destination for traffic. This restriction does not apply to HTTP proxies.
Interaction between HTTP and TCP
To understand how ports are handled in HTTP and TCP proxy servers, let's assume that you have two services: on 192.0.2.1:8080 and 192.0.2.1:8081, and a proxy server running on 198.51.100.1. If they differ by IP address and not by port number, this example will be like this the same, except for the corresponding address for each service. If they are expecting HTTP traffic to one HTTP proxy port, requests to both TCP endpoints can be sent to it. When HTTP sees that a message is addressed to 192.0.2.1:8080, the proxy redirects the message to that address or applies any rules it has for that service. The same procedure applies to 192.0.2.1:8081 using the same port.
If these two services are instead waiting for TCP traffic, two TCP proxy ports defined by two elements in the configuration file should be open:
The client configuration for the first service changes from "192.0.2.1:8080" to "198.51.100.1:3333", and for the second — from "192.0.2.1:8081" to "198.51.100.1:3334". The client sends a message (TCP packet) to the first service at the first address.
The proxy server receives it on this port (3333), but does not know what data is being sent over this connection. All he knows is the connection to port 3333. Therefore, the proxy server consults its configuration and sees that traffic to this port should be redirected to 192.0.2.1:8080 (or that a rule for this service should be applied to it). If you cannot redirect all your HTTP traffic because the client configuration does not support the HTTP proxy configuration, you should use a reverse HTTP proxy.
In it, instead of the target URL, you specify the one you need. This process is similar to the process of configuring a TCP proxy server, in which you specify it as a TCP endpoint for a message in the client system and create a forwarding rule.
Source: https://www.xn--hostng-s9a.com/blog/localhost-8080