Command line for looking at specific port
Here is the easy solution of port finding… In cmd: In bash: In PowerShell:
networking
How do I resolve the “java.net.BindException: Address already in use: JVM_Bind” error?
Yes you have another process bound to the same port. TCPView (Windows only) from Windows Sysinternals is my favorite app whenever I have a JVM_BIND error. It shows which processes are listening on which port. It also provides a convenient context menu to either kill the process or close the connection that is getting in the way.
Will setting a multicast destination address to FFFF.FFFF.FFFF make it a broadcast?
I’m working with a device that sends out UDP packets on a multicast address, however I see some packets addressed to the multicast group IP with a MAC address of FFFF.FFFF.FFFF. From what I’ve read my best guess is that this is an attempt to do a network wide broadcast from the multicast group. Here’s … Read more
What is the difference between a port and a socket?
This was a question raised by one of the software engineers in my organisation. I’m interested in the broadest definition.
java.net.ConnectException :connection timed out: connect?
The error message says it all: your connection timed out. This means your request did not get a response within some (default) timeframe. The reasons that no response was received is likely to be one of: a) The IP/domain or port is incorrect b) The IP/domain or port (i.e service) is down c) The IP/domain … Read more
ssh: Could not resolve hostname [hostname]: nodename nor servname provided, or not known
Recently I came across the same issue. I was able to ssh to my pi on my network, but not from outside my home network. I had already: installed and tested ssh on my home network. Set a static IP for my pi. Set up a Dynamic DNS service and installed the software on my … Read more
Socket Programming in C++
You can find a working client-server program here: Beej’s Guide to Network Programming
Networking with C++
Given your newness to C++, I would not recommend building directly on the sockets APIs unless you can find no suitable library to use. Boost.Asio will give you a huge head start and expose you to the higher-level abstractions used in network programming. It’s easy when starting out building a sockets-based system to get something that ‘sort … Read more
Connect: Socket operation on non-socket
I see the problem. It’s this line: The == operator has precedence over the = operator. Look at the way you have the parentheses structured on that expression a bit more carefully to see what I mean. sockfd is getting initialize to “0” as a result of being assigned a boolean expression (socket(…) == -1). … Read more
Connect: Socket operation on non-socket
I see the problem. It’s this line: The == operator has precedence over the = operator. Look at the way you have the parentheses structured on that expression a bit more carefully to see what I mean. sockfd is getting initialize to “0” as a result of being assigned a boolean expression (socket(…) == -1). … Read more