One possibility is to use TCP port forwarding. E.g. To open it back up as a listener you need to start tomcat, or any other program that you want, to listen on that port. At that point, your program is listening on multiple sockets. For opening a UDP port, type the following command: ★ iptables -A INPUT -p udp -sport portno -j ACCEPT where portno needs to be replaced with the numerical port number that you want to open. By default, Apache web server is instructed to listen for incoming connection and bind on port 80. You stopped it so now nothing is listening on that port. by Shahriar Shovon. 2 years ago. Call listen on the socket so that it's set up with a listen queue. The sockfd argument is a file descriptor that refers to a socket of type SOCK_STREAM or SOCK_SEQPACKET.. To listen on a port you need a program set up to do that. Der Grund dafür liegt darin, dass normale Benutzer auf einem Linux-System keine standardisierten Dienste (Webserver, Mailserver, etc.) List USB Devices Linux. How can I do this as simplest as possible on Linux? It has no effect on what, if anything, is listening on the port. Almost every device has a USB version of it. In your original case, tomcat was that program. anbieten sollten. If you opt for the TLS configuration, the server will listen for secure connections on port 443. using socat: socat TCP4-LISTEN:www,reuseaddr,fork TCP4:localhost:8080 However one disadvantage with that method is, the application that is listening on port 8080 then doesn't know the source address of incoming connections (e.g. Ziel-Port - Die Portnummer auf der Server-Seite ist in der Regel < 1024. The backlog argument defines the maximum length to which the queue of pending connections for sockfd may grow. An example is appreciated! Da diese Ports nur vom root-Benutzer geöffnet werden dürfen, bezeichnet man sie auch als privilegierte Ports. Here, we have assumed that you have logged in as the root user and have the superuser access. On Linux, I want to send a command string (i.e. listen() marks the socket referred to by sockfd as a passive socket, that is, as a socket that will be used to accept incoming connection requests using accept(2).. for logging or other identification purposes). This should clear your concepts on how to open a port in Linux. some data) to a serial port (containing control characters), and listen to the response (which also usually might contain control characters). In the world of USB computer peripherals, almost everyone uses some sort of USB devices in their computer. In order to accept connections on those … What program you select to listen on that port is entirely dependent on what service … These days there are USB webcams, USB hard drives, USB stick also known as PenDrive etc.