233 lines
5.6 KiB
HTML
233 lines
5.6 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>X11 Forwarding using SSH</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="Linux XDMCP HOWTO"
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TITLE="The Procedure"
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TITLE="Troubleshooting"
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>Linux XDMCP HOWTO</TH
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><DIV
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><H1
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CLASS="SECT1"
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><A
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NAME="SSH"
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></A
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>3. X11 Forwarding using SSH</H1
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><P
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> As I have explained earlier, using XDMCP to display X across Internet is basically a no-no, due to it's lack of
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encryption across the Internet. One way to enforce the traffic security is to use the SSH by the way of
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X11 tunnelling or port forwarding. SSH (Secure Shell) is developed in 1995 by Tatu Ylonen to replace the insecure telnet, ftp,
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scp, rcp, rlogin, rsh, etc. The first thing you need to know is that X11 forwarding using SSH is different from
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your regular, non-secure way of running X Window.
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</P
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><P
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>
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To start this setup, you need an additional piece of information. First, you must have your SSH package installed.
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In Linux, they are the OpenSSH packages. Check your distribution to decide what package you need to install (some installed it
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as standard packages). Secondly, you need a Windows SSH Client (other OS version, like MAC, are also available).
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I recommend PuTTY. It is a wonderful free SSH client and you can download them from
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<A
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HREF="http://www.chiark.greenend.org.uk/~sgtatham/putty/"
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TARGET="_top"
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>this link</A
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>. Remember to download the document and read
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them carefully. The other good free SSH clients are: Tera Term Pro + TTSSH: An SSH Extension to Tera Term, SSH Secure Shell
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Client by SSH.com (only free for non-commercial use). I will break down again into steps, so it is easy for you to follow.
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</P
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><P
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></P
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><OL
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TYPE="1"
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><LI
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><P
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> Open up the command <B
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CLASS="COMMAND"
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>putty.exe</B
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> by double-click it. It will brings up the interface. First,
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setup the connection info in Host Name (or use IP) field and select SSH (SSH is using port 22). In Connection Category,
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find the Connection tree. In SSH, expand it and you will see Tunnels window. Click "Enable X11 forwarding". It is setting the
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default to X display at "localhost:0". Now, go back to Session and save this session with a name you like. I normally use the
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Host Name to make me easily remember where I am connecting to.
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</P
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></LI
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><LI
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><P
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> In the example of Hummingbird Exceed, this is what you need to do. (For other X client, the setup is similar).
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Open up the Xconfig from your Exceed folder. In your "Screen Definition", change to "Multiple" Window mode and save it.
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Next, open up your "Communication" icon and set the Startup mode to "Passive".
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</P
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></LI
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><LI
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><P
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> Now you are done. To test it, first using PuTTY (or other SSH client) to connect to your server. The first time
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connection, it will ask you whether you want to cache the Security Key or not. (Yes is normal choice). Once log in is done,
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fire up your Exceed. It will stay in the background. Now you can execute any of your X application and it should forward the
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X application via SSH to your local screen. For example:
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="90%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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>$ xclock &</PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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> We should now see the Xclock is running on your local screen. </P
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></LI
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></OL
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><P
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>
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Now you see the difference is that you do not see all your X Window. You are simply running X application one by one and
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forwarding via SSH to your local screen. Therefore, you need to know the command for running each X application. All the
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control are done via SSH client window. To me, the security is worthy than the slightly inconvenience!
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</P
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><P
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>
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Hummingbird Exceed's newer version now support the SSH connection. I am sure other X application may be able to do the same in their
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latest new version. Check the application web site you are using or the <A
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HREF="#REFS"
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TARGET="_top"
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>Resources</A
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> belowfor for more details).
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</P
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><P
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>If you are using X-Win32 and you want to use <A
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HREF="http://www.starnet.com/products/ssh.htm"
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TARGET="_top"
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>SSH with Port Forwarding</A
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>,
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you can use this reference to set it up.
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</P
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></DIV
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CLASS="NAVFOOTER"
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>Prev</A
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>The Procedure</TD
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> |