<div dir="ltr"><div>A big problem with the netcat method is that it doesn't have authentication. If you can restrict the access to the port via a firewall so access is granted only from a single source, it wouldn't be as bad but the ip address could be spoofed. A direct physical connection would provide a secure-ish solution to that.<br><br></div>Whether you use a ssh tunnel or netcat, it amounts to the same (a proxy). With the ssh tunnel, it is far more secure.<br><br>jason<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Dec 4, 2014 at 4:22 PM, Michael P. Flaga <span dir="ltr"><<a href="mailto:michael@flaga.net" target="_blank">michael@flaga.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div link="blue" vlink="purple" lang="EN-US"><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Yes, I can create a tunnel over, but not forwarded onto another IP, rather need a bash prompt. So that the telneting program can call bash commands at the remote linux box.<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">The goal is to not simply tunnel the telnet. But rather translate it. Noting that telnetd is gone from the remote linux box. <u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Netcat is there, so “-t” will answer TELNET negotiation in place of telnetd.<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d">Michael P. Flaga, <a href="mailto:michael@flaga.net" target="_blank">michael@flaga.net</a></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Jason L. Froebe [mailto:<a href="mailto:jason.froebe@gmail.com" target="_blank">jason.froebe@gmail.com</a>] <br><b>Sent:</b> Thursday, December 04, 2014 4:12 PM<br><b>To:</b> Michael Flaga<br><b>Cc:</b> GLLUG<br><b>Subject:</b> Re: [GLLUG] Netcat Bash prompt<u></u><u></u></span></p><div><div class="h5"><p class="MsoNormal"><u></u> <u></u></p><p>On the windows box, use putty to create a ssh tunnel to your Linux box. This way nothing is transferred unencrypted over the network. <u></u><u></u></p><p>Jason<u></u><u></u></p><div><p class="MsoNormal">On Dec 4, 2014 4:02 PM, "Michael P. Flaga" <<a href="mailto:michael@flaga.net" target="_blank">michael@flaga.net</a>> wrote:<u></u><u></u></p><div><div><p class="MsoNormal">I have closed source programs that telnet on windows boxes. Where I am constrained to Linux Jump servers. That now only have SSH. The Telnet is GONE on the jump servers. The closed source programs once connected (formerly via telnet) to the jump servers then know who to issue the commands to ssh into the remote targets.<u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal">I need a way to translate Telnet to SSH on the jump servers.<u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal">The netcat on the jump servers do not have the –e option, so I cannot run nc in telnet mode into /bin/bash. <u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal">I have found <u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal">mkfifo pipe_name_in<u></u><u></u></p><p class="MsoNormal">mkfifo pipe_name_out<u></u><u></u></p><p class="MsoNormal">nc -l 5555 < pipe_name_out | /bin/bash > pipe_name_in<u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal">which kind of works. However, the Standard Error does not go down the pipe. <u></u><u></u></p><p class="MsoNormal">So I don’t get any echo or prompts, only the response.<u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal">nc -l 5555 < pipe_name_out | /bin/bash 2> pipe_name_in<u></u><u></u></p><p class="MsoNormal">does get the some of the prompts but then no responses.<u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal">nc -l 5555 < pipe_name_out | /bin/bash 2>&1 pipe_name_in<u></u><u></u></p><p class="MsoNormal">fails to allow connections.<u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal">Any suggestions or solutions?<u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d">Michael P. Flaga, <a href="mailto:michael@flaga.net" target="_blank">michael@flaga.net</a></span><u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p></div></div><p class="MsoNormal" style="margin-bottom:12.0pt"><br>_______________________________________________<br>linux-user mailing list<br><a href="mailto:linux-user@egr.msu.edu" target="_blank">linux-user@egr.msu.edu</a><br><a href="http://mailman.egr.msu.edu/mailman/listinfo/linux-user" target="_blank">http://mailman.egr.msu.edu/mailman/listinfo/linux-user</a><u></u><u></u></p></div></div></div></div></div></blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature">To stay young requires unceasing cultivation of the ability to unlearn
old falsehoods. -- Lazarus Long, "Time Enough For Love"</div>
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