Conserver Telnet

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Telnet, again...

 

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MFerreira at comstore  Sep 4, 2006, 7:12 AM  Post #1 of 7 (3885 views)  Permalink

Telnet, again... Remove Highlighting I have set a small lab to test conserver for my needs. The setup is quite simple: a standard PC, loaded with CentOS (Linux kernel 2.6), 2 serial ports (com-1 and com-2), 2 switches for testing the console access. Everything works great when using the console client. Almost the same for the telnet, I can log in, use the escape sequence to "call" a port and finally use the same escape sequence to connect ("^Ec;"). However, when I start using the connection it works like if I where pressing the enter key twice... This happens only when I connect to any equipment console. If I crossover the two serial ports, it works well.  My conserver (version 8.1.14) conserver.cf :  default * {  logfile /var/consoles/&.log;  timestamp 1hab;  rw *;  master localhost;  baud 9600;  parity none;  options !ixon, !ixoff;  host unused;  }  console s1 { type device; device /dev/ttyS0; }  console s2 { type device; device /dev/ttyS1; }  access * {  trusted 127.0.0.1;  allowed 0.0.0.0/0;  }  Any hint? Is it a bug or a bad configuration?  Thanks,  Moacir Ferreira

zonker at jeffk  Sep 4, 2006, 11:58 AM  Post #2 of 7 (3811 views)  Permalink

Re: Telnet, again... Remove Highlighting [In reply to] It sounds like your TTY may be set for "local echo"... if you  have NOTHING connected to the port, and use telnet to connect,  and then type, you see the characters, correct? The 'double  characters' come from your terminal displaying what you type,  and then the character is returned from the remote device...  In normal operation, you would NOT see what you typed...it  would only be sent to the 'far end', and you would rely on the  far device to return your keystrokes...  To test this theory, conect it to something that wants a password  to log in...type the username as norlam (you will see the double  characters, but the far end will only see one of each)...when you  type the password, one character will be "clear text", and the other  will be an asterisk (*, if the system masks the input), or you may  only see the single clear-text password if the system doesn't show  any masking characters.  Take a look at your termcap?  -Z-  _______________________________________________  users mailing list  users [at] conserver  https://www.conserver.com/mailman/listinfo/users

MFerreira at comstore  Sep 4, 2006, 2:10 PM  Post #3 of 7 (3803 views)  Permalink

RE: Telnet, again... Remove Highlighting [In reply to] Hi David,  Thanks for your help.  As soon as I connect (after "^Ec;"), when I press enter once the remote system CLI (Command Line Interface) of the switch will send a "login:" prompt. However, it shows it twice like if I had pressed enter twice. So I can't login because the same happens to the passord...  I am trying to "buy" a dynamic DNS to give public access to my lab, so anyone can come in, check it, change it, try it, etc. By the way, I forgot to mention that I am using getty as the Telnet client. So the full lab environment is:  An Intel IBM-PC;  CentOS 4.2 (Linux kernel 2.6);  The standard IBM PC serial pors (COM1, COM2);  The config I published in my first e-mail;  Getty as the Telnet client;  Logging in as "root";  An Alcatel switch and a 3Com ADSL modem as console to be remotely accessed;  Any help will be appreciated!  Thanks,  Moacir Ferreira  ________________________________  From: David K. Z. Harris on behalf of David K. Z. Harris  Sent: Mon 9/4/2006 7:58 PM  To: Moacir Ferreira; users [at] conserver  Subject: Re: Telnet, again...  It sounds like your TTY may be set for "local echo"... if you  have NOTHING connected to the port, and use telnet to connect,  and then type, you see the characters, correct? The 'double  characters' come from your terminal displaying what you type,  and then the character is returned from the remote device...  In normal operation, you would NOT see what you typed...it  would only be sent to the 'far end', and you would rely on the  far device to return your keystrokes...  To test this theory, conect it to something that wants a password  to log in...type the username as norlam (you will see the double  characters, but the far end will only see one of each)...when you  type the password, one character will be "clear text", and the other  will be an asterisk (*, if the system masks the input), or you may  only see the single clear-text password if the system doesn't show  any masking characters.  Take a look at your termcap?  -Z-

hakansom at ohsu  Sep 5, 2006, 10:12 AM  Post #4 of 7 (3802 views)  Permalink

Re: Telnet, again... Remove Highlighting [In reply to] > However, when I start using the connection it works like if I where =  > pressing the enter key twice... This happens only when I connect to any =  > equipment console.  There's a telnet option which maps EOL to <CR><LF>; You'll want to  turn that off for certain consoles. E.g. for Unix-based telnet client,  it's probably "unset crlf", or something similar.  Regards,  Marion  _______________________________________________  users mailing list  users [at] conserver  https://www.conserver.com/mailman/listinfo/users

MFerreira at comstore  Sep 5, 2006, 2:33 PM  Post #5 of 7 (3785 views)  Permalink

RE: Telnet, again... Remove Highlighting [In reply to] Sorry for my late answers but I am at London time...  I have tested it using Tera Term, Putty, Microsoft Telnet (Windows XP) and Linux telnet. Tera Term won't work. Linux Telenet will get "loose" once I try to connect (after "^Ec;"), Putty and Microsoft Telnet works like the same, after "^Ec;" when I press enter I get the "login:" message twice. I wish I can make my test lab public so you can come in and check what is wrong.  If anyone reading this thread has already faced this problem, please let me know how to overcome it! It must be something I am doing wrong... Conserver is already a "mature" product so it must be my fault...  Moacir  ________________________________  From: users-bounces [at] conserver on behalf of Marion Hakanson  Sent: Tue 9/5/2006 6:12 PM  To: Moacir Ferreira  Cc: David K. Z. Harris; users [at] conserver  Subject: Re: Telnet, again...  > However, when I start using the connection it works like if I where =  > pressing the enter key twice... This happens only when I connect to any =  > equipment console.  There's a telnet option which maps EOL to <CR><LF>; You'll want to  turn that off for certain consoles. E.g. for Unix-based telnet client,  it's probably "unset crlf", or something similar.  Regards,  Marion  _______________________________________________  users mailing list  users [at] conserver  https://www.conserver.com/mailman/listinfo/users

hakansom at ohsu  Sep 5, 2006, 3:19 PM  Post #6 of 7 (3805 views)  Permalink

Re: Telnet, again... Remove Highlighting [In reply to] MFerreira [at] comstore said:  > I have tested it using Tera Term, Putty, Microsoft Telnet (Windows XP) and  > Linux telnet. Tera Term won't work. Linux Telenet will get "loose" once I try  > to connect (after "^Ec;"), Putty and Microsoft Telnet works like the same,  > after "^Ec;" when I press enter I get the "login:" message twice. I wish I  > can make my test lab public so you can come in and check what is wrong.  I've used putty in this mode to connect to an IOLAN Rack+ (reverse telnet).  To get rid of the "double return" problem, after you've started the putty  connection, right-click on the top of the putty window, select the  "Change Settings" item, then "Telnet", then de-select the check-box  labelled "Return key sends Telnet New Line instead of ^M". Can't help  you with the other telnet clients.  Regards,  Marion  _______________________________________________  users mailing list  users [at] conserver  https://www.conserver.com/mailman/listinfo/users

MFerreira at comstore  Sep 7, 2006, 3:14 AM  Post #7 of 7 (3803 views)  Permalink

RE: Telnet, again... Remove Highlighting [In reply to] Thanks for your help Marion. I tested what you said using Putty and the behaviour has changed. I let Putty with its original setup up to the "^Ec;" sequence then I do what you say. Now when I press the return key Conserver I will get a single "^@login:" and it should be just "login:". Then I type the logon name (in my case "admin") and hit enter again and I will get a "admin" reply followed by a new line showing "^@login:" again and I can't login. Now I am sure that, for somehow, Conserver does not behave well when we connect to the server using Telnet. The first question I have is: Does anyone know any Telnet client that could be used in a Windows environment?  By other hand, it would be perfect if I let people login remotely to the Conserver box (lets say using Putty over SSH that is perfect for security reasons) and then let this user run the original Conserver console client. However, I am pretty dumb when it comes to configure Linux. I don't know how to configure it so the remote user could not mess with the server... So, alternatively to my question above, does anyone in this thread knows a "howto" for dummies for setting up this remote access without allowing a user to mess with the server?  Reading the e-mail threads about Telnet I could see that people does not understand why would someone use Telnet and Windows... I am trying to assemble a network lab where my clients could come in and do tests and configurations on my switches/routers for learning/testing proposes. Most of these clients are Windows oriented people. However, Putty is widely used tool, what would make my life very easy if I could use it as the remote client. Much better than this would be securing my system so my clients could Telnet over SSH, get a standard Linux console and use the original Conserver console client.  Thanks again!  ________________________________  From: users-bounces [at] conserver on behalf of Marion Hakanson  Sent: Tue 9/5/2006 11:19 PM  To: Moacir Ferreira  Cc: David K. Z. Harris; users [at] conserver  Subject: Re: Telnet, again...  MFerreira [at] comstore said:  > I have tested it using Tera Term, Putty, Microsoft Telnet (Windows XP) and  > Linux telnet. Tera Term won't work. Linux Telenet will get "loose" once I try  > to connect (after "^Ec;"), Putty and Microsoft Telnet works like the same,  > after "^Ec;" when I press enter I get the "login:" message twice. I wish I  > can make my test lab public so you can come in and check what is wrong.  I've used putty in this mode to connect to an IOLAN Rack+ (reverse telnet).  To get rid of the "double return" problem, after you've started the putty  connection, right-click on the top of the putty window, select the  "Change Settings" item, then "Telnet", then de-select the check-box  labelled "Return key sends Telnet New Line instead of ^M". Can't help  you with the other telnet clients.  Regards,  Marion  _______________________________________________  users mailing list  users [at] conserver  https://www.conserver.com/mailman/listinfo/users