Questions tagged [tcp]
Transmission Control Protocol (TCP) is a transport layer protocol that provides a connection-oriented data stream service with delivery that is guaranteed to be in-order.
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Who is listening on a given TCP port on Mac OS X?
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?
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What does "connection reset by peer" mean?
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?
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How can I connect to Android with ADB over TCP? [closed]
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 ...
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What is the largest TCP/IP network port number allowable for IPv4?
What is the highest port number one can use?
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How do multiple clients connect simultaneously to one port, say 80, on a server? [duplicate]
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 ...
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How do I debug error ECONNRESET in Node.js?
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 ...
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Artificially create a connection timeout error
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 ...
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Test if remote TCP port is open from a shell script
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 ...
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Can two applications listen to the same port?
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 ...
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When is it appropriate to use UDP instead of TCP? [closed]
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 ...
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What is the theoretical maximum number of open TCP connections that a modern Linux box can have
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 ...
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Simulate delayed and dropped packets on Linux
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?
Alec
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java.net.ConnectException: Connection refused
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: ...
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What is the difference between HTTP 1.1 and HTTP 2.0? [closed]
HTTP/1.1 has served the Web well for more than fifteen years, but its
age is starting to show.
Can anybody explain what is the main difference between HTTP 1.1 and 2.0?
Is there any change in the ...
user1968030
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Maximum packet size for a TCP connection
What is the maximum packet size for a TCP connection or how can I get the maximum packet size?
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UDP vs TCP, how much faster is it? [closed]
For general protocol message exchange, which can tolerate some packet loss. How much more efficient is UDP over TCP?
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Differences between TCP sockets and web sockets, one more time [duplicate]
Trying to understand as best as I can the differences between TCP socket and websocket, I've already found a lot of useful information within these questions:
fundamental difference between ...
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What is the fundamental difference between WebSockets and pure TCP?
I've read about WebSockets and I wonder why browser couldn't simply open trivial TCP connection and communicate with server like any other desktop application. And why this communication is possible ...
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Why is SCTP not much used/known
I recently checked out the book "UNIX Network Programming, Vol. 1" by Richards Stevens and I found that there is a third transport layer standard besides TCP and UDP: SCTP.
Summary: SCTP is a ...
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TCP: can two different sockets share a port?
This might be a very basic question but it confuses me.
Can two different connected sockets share a port? I'm writing an application server that should be able to handle more than 100k concurrent ...
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Freeing up a TCP/IP port? [closed]
netstat -tulnap
shows me what ports are in use. How to free up a port in Linux?
bapi
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NGINX to reverse proxy websockets AND enable SSL (wss://)?
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 ...
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How do ports work with IPv6?
Conventional IPv4 dotted quad notation separates the address from the port with a colon, as in this example of a webserver on the loopback interface:
127.0.0.1:80
but with IPv6 notation the address ...
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Telnet is not recognized as internal or external command, even after activation [closed]
I am trying to perform port forwarding to connect two emulators using TCP protocol on Windows.
Although I have enabled TCP client program from control Panel, "telnet" command is not ...
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ConnectionTimeout versus SocketTimeout
I'm having a problem with a library that I am using. It might be the library or it might be me using it wrong!
Basically, when I do this (Timeout in milliseconds)
_ignitedHttp.setConnectionTimeout(1)...
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How many socket connections can a web server handle?
Say if I was to get shared, virtual or dedicated hosting, I read somewhere a server/machine can only handle 64,000 TCP connections at one time, is this true? How many could any type of hosting handle ...
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Check status of one port on remote host [closed]
I need a command line that can check the port status on a remote host. I tried ping xxx.xxx.xxx.xxx:161 but it doesn't recognize the "host". I thought it was a "good" answer until I did the same ...
Sheila
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What causes a TCP/IP reset (RST) flag to be sent?
I'm trying to figure out why my app's TCP/IP connection keeps hiccuping every 10 minutes (exactly, within 1-2 seconds). I ran Wireshark and discovered that after 10 minutes of inactivity the other ...
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TCP loopback connection vs Unix Domain Socket performance
Working on an Android and iOS based application which require communication with a server running in the same device. Currently using TCP loopback connection for communicating with App and Server (App ...
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Difference between TCP and UDP?
What is the difference between TCP and UDP?
I know that TCP is used in the case of non-time critical applications, and UDP is used for games or applications that require fast transmission of data. I ...
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How to write a scalable TCP/IP based server
I am in the design phase of writing a new Windows service application that accepts TCP/IP connections for long running connections (i.e., this is not like HTTP where there are many short connections, ...
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In C#, how to check if a TCP port is available?
In C# to use a TcpClient or generally to connect to a socket how can I first check if a certain port is free on my machine?
more info:
This is the code I use:
TcpClient c;
//I want to check here if ...
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How does the socket API accept() function work?
The socket API is the de-facto standard for TCP/IP and UDP/IP communications (that is, networking code as we know it). However, one of its core functions, accept() is a bit magical.
To borrow a semi-...
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HTTP vs TCP/IP, send data to a web server
I'm currently working on a project where I need to use an Arduino Nano (http://arduino.cc/en/Main/arduinoBoardNano) to send data from a temperature sensor to a web server.
At first I thought it would ...
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Can TCP and UDP sockets use the same port?
First of all, is there any problem with using both UDP and TCP on the same server?
Secondly, can I use the same port number?
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How should one go about choosing a default TCP/IP port for a new service?
When developing an app that will listen on a TCP/IP port, how should one go about selecting a default port? Assume that this app will be installed on many computers, and that avoiding port conflicts ...
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Linux: is there a read or recv from socket with timeout?
How can I try to read data from socket with timeout?
I know, select, pselect, poll, has a timeout field, but using of them disables "tcp fast-path" in tcp reno stack.
The only idea I have is to use ...
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When is TCP option SO_LINGER (0) required?
I think I understand the formal meaning of the option. In some legacy code I'm handling now, the option is used. The customer complains about RST as response to FIN from its side on connection close ...
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How to convert from []byte to int in Go Programming
I need to create a client-server example over TCP. In the client side I read 2 numbers and I send them to the server. The problem I faced is that I can't convert from []byte to int, because the ...
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Does a TCP socket connection have a "keep alive"?
I have heard of HTTP keep-alive but for now I want to open a socket connection with a remote server.
Now will this socket connection remain open forever or is there a timeout limit associated with it ...
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WebSockets ping/pong, why not TCP keepalive?
WebSockets have the option of sending pings to the other end, where the other end is supposed to respond with a pong.
Upon receipt of a Ping frame, an endpoint MUST send a Pong frame in
response, ...
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TCP vs UDP on video stream
I just came home from my exam in network-programming, and one of the question they asked us was "If you are going to stream video, would you use TCP or UDP? Give an explanation for both stored video ...
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Do I need to heartbeat to keep a TCP connection open?
I have two components that that communicate via TCP/IP. Component A acts as a server/listener and Component B is the client. The two should communicate as quickly as possible. There can only ever ...
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Why is network-byte-order defined to be big-endian? [closed]
As written in the heading, my question is, why does TCP/IP use big endian encoding when transmitting data and not the alternative little-endian scheme?
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Does WebRTC use TCP or UDP?
I have some questions about WebRTC:
Does WebRTC use TCP or UDP as its peer-to-peer transport? How can I
know?
I read that there are reliability mode and DTLS agreement, how does
these affect?
Is this ...
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What do you use when you need reliable UDP?
If you have a situation where a TCP connection is potentially too slow and a UDP 'connection' is potentially too unreliable what do you use? There are various standard reliable UDP protocols out there,...
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Can I use tcpdump to get HTTP requests, response header and response body?
I am using tcpdump to get HTTP data by executing the below command:
sudo tcpdump -A -s 1492 dst port 80
The result of above command:
Headers, I think request and response headers.
...
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Detecting TCP Client Disconnect
Let's say I'm running a simple server and have accept()ed a connection from a client.
What is the best way to tell when the client has disconnected? Normally, a client is supposed to send a close ...
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What is SOCK_DGRAM and SOCK_STREAM?
I just came across this strange thing I got to see application is that by default they use SOCK_STREAM function. Why is it so? Is this SOCK_STREAM just creating multiple streams? Or is it the ...
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Simple Socket Server in Bash?
Is there a way to quickly bind to a TCP port/ip address and simply print out all information to STDOUT? I have a simple debugging solution which writes things to 127.0.0.1:4444 and I'd like to be able ...
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