<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style></style></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1>Authentication aside. The client app is only Telnet. So it must get terminated (somehow) at the Linux box with Telnet to a bash.<o:p></o:p><o:p> </o:p>If need, it can be more secure by using a ssh tunnel between boxes and configuring the local telnet client to the tunnel. <o:p></o:p><o:p> </o:p>Michael P. Flaga, <a href="mailto:michael@flaga.net">michael@flaga.net</a><o:p></o:p><o:p> </o:p>From: Jason L. Froebe [mailto:jason.froebe@gmail.com] Sent: Thursday, December 04, 2014 5:18 PM To: Michael Flaga Cc: GLLUG Subject: Re: [GLLUG] Netcat Bash prompt<o:p></o:p><o:p> </o:p><div><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.<o:p></o:p></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. jason<o:p></o:p></div><div><o:p> </o:p><div>On Thu, Dec 4, 2014 at 4:22 PM, Michael P. Flaga <<a href="mailto:michael@flaga.net" target="_blank">michael@flaga.net</a>> wrote:<o:p></o:p><div><div>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.<o:p></o:p> <o:p></o:p>The goal is to not simply tunnel the telnet. But rather translate it. Noting that telnetd is gone from the remote linux box. <o:p></o:p> <o:p></o:p>Netcat is there, so “-t” will answer TELNET negotiation in place of telnetd.<o:p></o:p> <o:p></o:p>Michael P. Flaga, <a href="mailto:michael@flaga.net" target="_blank">michael@flaga.net</a><o:p></o:p> <o:p></o:p>From: Jason L. Froebe [mailto:<a href="mailto:jason.froebe@gmail.com" target="_blank">jason.froebe@gmail.com</a>] Sent: Thursday, December 04, 2014 4:12 PM To: Michael Flaga Cc: GLLUG Subject: Re: [GLLUG] Netcat Bash prompt<o:p></o:p><div><div> <o:p></o: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. <o:p></o:p>Jason<o:p></o:p><div>On Dec 4, 2014 4:02 PM, "Michael P. Flaga" <<a href="mailto:michael@flaga.net" target="_blank">michael@flaga.net</a>> wrote:<o:p></o:p><div><div>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.<o:p></o:p> <o:p></o:p>I need a way to translate Telnet to SSH on the jump servers.<o:p></o:p> <o:p></o:p>The netcat on the jump servers do not have the –e option, so I cannot run nc in telnet mode into /bin/bash. <o:p></o:p> <o:p></o:p>I have found <o:p></o:p> <o:p></o:p>mkfifo pipe_name_in<o:p></o:p>mkfifo pipe_name_out<o:p></o:p>nc -l 5555 < pipe_name_out | /bin/bash > pipe_name_in<o:p></o:p> <o:p></o:p>which kind of works. However, the Standard Error does not go down the pipe. <o:p></o:p>So I don’t get any echo or prompts, only the response.<o:p></o:p> <o:p></o:p>nc -l 5555 < pipe_name_out | /bin/bash 2> pipe_name_in<o:p></o:p>does get the some of the prompts but then no responses.<o:p></o:p> <o:p></o:p>nc -l 5555 < pipe_name_out | /bin/bash 2>&1 pipe_name_in<o:p></o:p>fails to allow connections.<o:p></o:p> <o:p></o:p>Any suggestions or solutions?<o:p></o:p> <o:p></o:p>Michael P. Flaga, <a href="mailto:michael@flaga.net" target="_blank">michael@flaga.net</a><o:p></o:p> <o:p></o:p></div></div> _______________________________________________ linux-user mailing list <a href="mailto:linux-user@egr.msu.edu" target="_blank">linux-user@egr.msu.edu</a> <a href="http://mailman.egr.msu.edu/mailman/listinfo/linux-user" target="_blank">http://mailman.egr.msu.edu/mailman/listinfo/linux-user</a><o:p></o:p></div></div></div></div></div></div> -- <o:p></o:p><div>To stay young requires unceasing cultivation of the ability to unlearn old falsehoods. -- Lazarus Long, "Time Enough For Love"<o:p></o:p></div></div></div></body></html>