282 lines
7.2 KiB
HTML
282 lines
7.2 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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>Connections to Servers</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 on the Road"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="Different Environments"
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HREF="mobile-guide-p5c1-different-environments.html"><LINK
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REL="PREVIOUS"
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TITLE="Backup"
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HREF="mobile-guide-p5c1s4-backups.html"><LINK
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REL="NEXT"
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TITLE="Security in Different Environments"
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HREF="mobile-guide-p5c1s5-security-in-different-environments.html"></HEAD
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><BODY
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CLASS="sect1"
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BGCOLOR="#FFFFFF"
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><DIV
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><TR
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>Linux on the Road: </TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="mobile-guide-p5c1s4-backups.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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>Chapter 15. Different Environments</TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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>Next</A
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ALIGN="LEFT"
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><DIV
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CLASS="sect1"
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><H1
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CLASS="sect1"
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><A
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NAME="mobile-guide-p5c1s4-connections-to-servers"
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></A
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>15.6. Connections to Servers</H1
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><P
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> From Dirk Janssen <dirkj_AT_u.arizona.edu>: Here are several good
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ways of working on your laptop from your desktop machine. If you have a
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separate desktop machine at work, you might want to use that as a
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terminal server to your laptop. This means you get the larger screen and
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the better keyboard, without having to worry about syncing files. The
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easiest way to do this is to install ssh on both sides, and ssh from
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your desktop (running X) to the laptop. Ssh will provide a secure
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connection and, crucially, a secure X connection between the two
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machines. If you type, for example, <B
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CLASS="command"
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>emacs &</B
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> in
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the ssh shell, emacs will start a window on your desktop machine while
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running on your laptop.
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</P
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><P
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> There are various ways in which you can make this situation more
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productive/complicated. Emacs, for one thing, can open windows (called
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frames by emacs) on separate displays by using
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<B
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CLASS="command"
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>make-frame-on-display</B
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>. This way, you can have the
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same emacs displaying on your desktop and your laptop: A dual headed
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system is born.
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</P
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><P
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> For other programs, you usually have to decide at startup time on which
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screen you want them. To run them on the laptop screen, start them as
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usual. To run them on the desktop screen, start them from the ssh shell
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on the desktop or redirect their screens using the DISPLAY variable.
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Some programs also accept a <B
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CLASS="command"
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>-display</B
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> option. Read the
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documentation on <B
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CLASS="command"
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>xauth</B
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> on how to set this up. An easy
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way out is to find out which pseudo display ssh has created for you by
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typing <B
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CLASS="command"
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>echo $DISPLAY</B
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> in the ssh shell. Assuming your
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desktop is called <B
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CLASS="command"
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>olli</B
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> and your laptop
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<B
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CLASS="command"
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>stan</B
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>, this will usually produce something like
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<B
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CLASS="command"
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>stan:10</B
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>. This means that processes on stan (the
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laptop) display on what they think is the 10th screen of stan, which by
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some ssh magic is actually relayed (in a secure way) to the screen of
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olli.
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</P
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><P
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> There are some ways in which you can dynamically move windows from one
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machine to another. A very interesting approach is taken by
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<B
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CLASS="command"
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>xmove</B
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>, but this program lacks a good user interface
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(any volunteers?). Xmove creates a pseudo screen (similar to the stan:10
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that ssh creates) and windows that have their DISPLAY set to this pseudo
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screen can be moved back and forth between real screens (provided all
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screens use the same color depth).
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</P
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><P
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> Alternatively, you can run an one of the several programs that open a
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<B
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CLASS="command"
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>virtual root window</B
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>: A window on your desktop that
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contains other windows. It looks a lot like running an emulator. With
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these programs, you can start your processes on stan, then move all
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their windows to olli, then work for a while, and then move them back so
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you can continue working on stan. Hibernate your laptop and repeat ad
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infinitum. Check out xmx and VNC for this.
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</P
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><P
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> If this is all too complicated for you, but you like to use the two
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screens at the same time, consider at least installing x2x. This little
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tool makes it possible to move your mouse from one screen to the other,
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and the keyboard focus goes with it. To run it, you need another ssh
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going from stan (the laptop) to olli (the desktop): ie. type
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<B
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CLASS="command"
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>ssh olli</B
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> in a stan xterm. Keep this shell running and
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find out which pseudo screen was created with <B
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CLASS="command"
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>echo
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$DISPLAY</B
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>. This will return something like
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<B
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CLASS="command"
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>olli:10</B
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> (see above for explanation). Now, type this
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in any shell on olli: <B
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CLASS="command"
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>x2x -west -to olli:10</B
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> (and I
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mean, in a shell that runs on olli and displays on olli, not an ssh
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shell) This creates a little black band to on the left (west) side of
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your desktop's screen. Whenever you move the mouse over this, the mouse
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on screen olli:10 will move. Because olli:10 is just an ssh-created
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alias for the screen of stan, the mouse on your laptop will move and you
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can type there by only moving your head, not your hands.
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</P
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><P
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> A note on X-security: Playing around with various screen programs is
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much easier if you issue an <B
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CLASS="command"
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>xhost +</B
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> on either
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computer. But this is extremely unsafe. Do this only when you are not
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connected to any larger network. If you have everything working, spend
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some time on getting xauth to work. If you use xdm, it is usually easy.
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Otherwise, consider starting your Xserver with the same magic cookie all
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the time. This is less safe, but still pretty safe, and it means that
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you have to copy the cookies only once. Check the startup scripts
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(.xserverrc, .xinitrc, .xsession, etc) for something like
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<B
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CLASS="command"
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>cookie="MIT-MAGIC-COOKIE-1 `keygen`"</B
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> and change that
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into (invent your own cookie here): <B
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CLASS="command"
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>cookie="MIT-MAGIC-COOKIE-1
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12345678901234567890abcdefabcdef"</B
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>
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</P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="mobile-guide-p5c1s4-backups.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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ACCESSKEY="H"
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>Home</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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><A
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HREF="mobile-guide-p5c1s5-security-in-different-environments.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Backup</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="mobile-guide-p5c1-different-environments.html"
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ACCESSKEY="U"
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>Up</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Security in Different Environments</TD
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></TR
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></TABLE
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></DIV
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></BODY
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> |