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An oversimplified introduction to sockets

Perl, Sockets and TCP/IP Networking

An oversimplified introduction to sockets

Sockets are a mechanism that allows programs to communicate, either on the same machine or across a network. The way it works is pretty simple: Each machine on a network is identified by some address. In this tutorial we will talk about tcp/ip networking, so by network address we mean an IP address. (like Apart from the IP address that specifies a machine, each machine has a number of ports that allow handling multiple connections simultaneously.

A program that wishes to receive a connection from another program, asks the operating system to create a socket and bind it to some port. Then the program sits and listens on the socket it has created to receive incoming connections. The other program also creates a socket for communicating witht he receiver. The caller needs to specify the IP address and the port number of the receiving end. If all goes well, and as we will see shortly, the two programs establish a communication through the network using their sockets. The two programs may exchange information, each by writing to and reading from the socket it has created.

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