TCP IP Illustrated

But well run a newer client bsd386 that tries to

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Unformatted text preview: ailable commands. We'll see examples of the client escape, and some of the commands we can issue, in the next section. 26.5 Telnet Examples We'll now look at Telnet option negotiation, along with the three different modes of operation: character at a time, real linemode, and kludge line mode. We also see what happens when an interactive user aborts a running process on the server with the interrupt key. Character-at-a-Time Mode We start with the basic character-at-a-time mode, similar to Rlogin. Each character we type on the terminal is sent by itself to the server, and the server echoes the character. But we'll run a newer client (BSD/386) that tries to enable many newer options, and see them refused by the older server (SVR4). To see what's negotiated between the client and server we'll enable a client option that displays all the option negotiation, and we'll also run tcpdump to obtain a time line of the packet exchange. Figure 26.12 shows the interactive session. bsdi % telnet invoke client without any command-line options telnet> toggle options tell client to display all the option processing Will show option processing. file:///D|/Documents%20and%20Settings/bigini/Docum...ti/homenet2run/tcpip/tcp-ip-illustrated/telnet.htm (19 of 26) [12/09/2001 14.47.45] Chapter 26. Telnet and Rlogin: Remote Login telnet> open svr4 Trying 140.252.13.34... Connected to svr4. Escape character is '^]'. now establish connection with server SENT DO SUPPRESS GO AHEAD SENT WILL TERMINAL TYPE SENT WILL NAWS SENT WILL TSPEED SENT WILL LFLOW SENT WILL LINEMODE SENT WILL ENVIRON SENT DO STATUS RCVD DO TERMINAL TYPE RCVD WILL SUPPRESS GO AHEAD RCVD DONT NAWS RCVD DONT TSPEED RCVD DONT LFLOW RCVD DONT LINEMODE RCVD DONT ENVIRON RCVD WONT STATUS RCVD IAC SB TERMINAL-TYPE SEND SENT IAC SB TERMINAL-TYPE IS "IBMPC3" RCVD WILL ECHO SENT DO ECHO RCVD DO ECHO SENT WONT ECHO 1. (line numbers for discussion that follows) 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. UNIX(r) System V Release 4.0 (svr...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.

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