How do I manually find (and kill) process using the terminal that listen to/use my TCP ports? I'm on macOS. Sometimes, after a crash or bug, my Rails app gets locked to port 3000, and I can't find it ...

On Linux, I can use netstat -pntl | grep $PORT or fuser -n tcp $PORT to find out which process (PID) is listening on the specified TCP port. How do I get the same information on Mac OS X?

What is the meaning of the "connection reset by peer" error on a TCP connection? Is it a fatal error or just a notification or related to the network failure?

I am attempting to debug an application on a Motorola Droid, but I am having some difficulty connecting to the device via USB. My development server is a Windows 7 64-bit VM running in Hyper-V, and so ...

What is the highest port number one can use?

I understand the basics of how ports work. However, what I don't get is how multiple clients can simultaneously connect to say port 80. I know each client has a unique (for their machine) port. Does ...

I'm running an Express.js application using Socket.io for a chat webapp and I get the following error randomly around 5 times during 24h. The node process is wrapped in forever and it restarts itself ...

I've had a bug in our software that occurs when I receive a connection timeout. These errors are very rare (usually when my connection gets dropped by our internal network). How can I generate this ...

I'm looking for a quick and simple method for properly testing if a given TCP port is open on a remote server, from inside a Shell script. I've managed to do it with the telnet command, and it works ...

Can two applications on the same machine bind to the same port and IP address? Taking it a step further, can one app listen to requests coming from a certain IP and the other to another remote IP? I ...

Since TCP guarantees packet delivery and thus can be considered "reliable", whereas UDP doesn't guarantee anything and packets can be lost. What would be the advantage of transmitting data using UDP ...

Assuming infinite performance from hardware, can a Linux box support >65536 open TCP connections? I understand that the number of ephemeral ports (<65536) limits the number of connections from one ...

I would like to simulate packet delay and loss for UDP and TCP on Linux to measure the performance of an application. Is there a simple way to do this?

I'm trying to implement a TCP connection, everything works fine from the server's side but when I run the client program (from client computer) I get the following error: java.net.ConnectException: ...

I'm so lost and new to building NGINX on my own but I want to be able to enable secure websockets without having an additional layer. I don't want to enable SSL on the websocket server itself but ...