CS 742 - TELNET Protocol

 1. Fire up a telnet client:

$ telnet

 2. Obtain a list of commands:

telnet> help
Commands may be abbreviated.  Commands are:

close           close current connection
logout          forcibly logout remote user and close the connection
display         display operating parameters
mode            try to enter line or character mode ('mode ?' for more)
open            connect to a site
quit            exit telnet
send            transmit special characters ('send ?' for more)
set             set operating parameters ('set ?' for more)
unset           unset operating parameters ('unset ?' for more)
status          print status information
toggle          toggle operating parameters ('toggle ?' for more)
slc             set treatment of special characters
z               suspend telnet
environ         change environment variables ('environ ?' for more)


 3. Connect to another machine:

telnet> open kirk
Trying 156.26.10.239...
Connected to kirk.cs.twsu.edu.
Escape character is '^]'.
Debian GNU/Linux 3.0 kirk.cs.twsu.edu
kirk login: cs742
Password:
Last login: Tue Dec  3 22:42:20 2002 from wireless.cs.twsu.edu on pts/23
Linux kirk 2.4.19 #1 SMP Fri Aug 16 18:48:17 CDT 2002 i686 unknown
Tinman news: java 1.4.1_01 is now on tinman.  Look in either
   /usr/local/j2sdk1.4.1 or /usr/local/j2sdk1.4.1_01 (linked to the
   same location).

Kira News:  the old machine kira is offline.  The new kira is a
four-processor Xeon-500 system with 2G of memory.   Please let me know if
anything that worked on the old system doesn't work anymore.

VI Users:

        Debian 3.0 uses vim by default.  It has several nice features, but
does not stick 100% to the old vi standard.  For users who wish to
use a more accurate vi, try nvi


You have mail.
Erase is delete.
Kill is control-U (^U).
Interrupt is control-C (^C).
cs742@kirk:~$

 4. Escape back to telnet client using <ctrl>-]:

telnet> status
Connected to kirk.cs.twsu.edu.
Escape character is '^]'.

 5. Display information about the session:

telnet> display
will flush output when sending interrupt characters.
won't send interrupt characters in urgent mode.
won't read the telnetrc files.
won't map carriage return on output.
will recognize certain control characters.
won't turn on socket level debugging.
won't print hexadecimal representation of network traffic.
won't print user readable output for "netdata".
won't show option processing.
won't print hexadecimal representation of terminal traffic.

echo            [^E]
escape          [^]]
rlogin          [off]
tracefile       "(standard output)"
flushoutput     [^O]
interrupt       [^C]
quit            [^\]
eof             [^D]
erase           [^?]
kill            [^U]
lnext           [^V]
susp            [^Z]
reprint         [^R]
worderase       [^W]
start           [^Q]
stop            [^S]
forw1           [off]
forw2           [off]
ayt             [^T]
     DO   ECHO
resp WILL_WONT ECHO: 1
want WONT ECHO
     DO   SUPPRESS GO AHEAD
     DO   STATUS
     WILL TERMINAL TYPE
     WILL NAWS
     WILL TSPEED
     WILL LFLOW
     WILL XDISPLOC
     WILL NEW-ENVIRON
display: Unable to connect to X server (localhost:13.0) [Connection refused].
cs742@kirk:~$

 6. Send a friendly (are you there?) from the client:

telnet> send ayt

[kirk.cs.twsu.edu : yes]

telnet>

 7. Exit from kirk and Terminate the telnet client:

kirk:~$ exit
logout
Connection closed by foreign host.
$