12.4 Example of UNIX Client Communication

Let’s say our client is started in an X-Windows window within the True64 UNIX system. The server is True64 UNIX as well.

An example of this communication is shown in the following figure:

Figure 12.4: Client/server communication in UNIX

We first start the Telnet program without a parameter and thus get the Telnet program command line. From here we start a listing of debugging information both of IAC in text form (1) and of all application data in hexadecimal notation (2).

We use the open command to establish communication with t1.pvt.cz server. The Telnet program sets the escape sequence as ^]. As the port number was not specified in the open command, the client (unlike Windows NT Client) assumes it is establishing connection with a Telnet protocol server. This is why immediately after the connection is established, the client sends these IAC commands of the Telnet protocol to the server:

• (5) The client does not want to communicate in half-duplex...