How does the socket API accept() function work?

by

Your confusion lies in thinking that a socket is identified by Server IP : Server Port. When in actuality, sockets are uniquely identified by a quartet of information:

Client IP : Client Port and Server IP : Server Port

So while the Server IP and Server Port are constant in all accepted connections, the client side information is what allows it to keep track of where everything is going.

Example to clarify things:

Say we have a server at 192.168.1.1:80 and two clients, 10.0.0.1 and 10.0.0.2.

10.0.0.1 opens a connection on local port 1234 and connects to the server. Now the server has one socket identified as follows:

10.0.0.1:1234 - 192.168.1.1:80

Now 10.0.0.2 opens a connection on local port 5678 and connects to the server. Now the server has two sockets identified as follows:

10.0.0.1:1234 - 192.168.1.1:80  
10.0.0.2:5678 - 192.168.1.1:80

More Related Contents:

  1. What is the difference between a port and a socket?
  2. When is TCP option SO_LINGER (0) required?
  3. What is the largest Safe UDP Packet Size on the Internet
  4. UDP vs TCP, how much faster is it? [closed]
  5. How to detect a remote side socket close? [duplicate]
  6. Maximum packet size for a TCP connection
  7. What causes a TCP/IP reset (RST) flag to be sent?
  8. What is the cost of many TIME_WAIT on the server side?
  9. When is it appropriate to use UDP instead of TCP? [closed]
  10. Can TCP and UDP sockets use the same port?
  11. Artificially create a connection timeout error
  12. Why is network-byte-order defined to be big-endian? [closed]
  13. Can a TCP checksum fail to detect an error? If yes, how is this dealt with?
  14. TCP Socket no connection timeout
  15. Java TCP socket: data transfer is slow
  16. TCP vs UDP on video stream
  17. TCP stream vs UDP message
  18. Sockets On Same Machine For Windows and Linux
  19. How to tell which interface the socket received the message from?
  20. How to close a socket left open by a killed program?
  21. How can I connect to Android with ADB over TCP? [closed]
  22. java.net.SocketException: Connection reset
  23. What is the difference between 127.0.0.1 and localhost
  24. Differences between TCP sockets and web sockets, one more time [duplicate]
  25. Do I need to heartbeat to keep a TCP connection open?
  26. How to find an available port?
  27. Windows Phone 8 emulator can’t connect to the internet
  28. Writing to a closed, local TCP socket not failing
  29. Blocking sockets: when, exactly, does “send()” return?
  30. What is “backlog” in TCP connections?

Leave a Comment