Synergy Frequently Asked Questions ================================== Questions --------- 1. Why doesn't ctrl+alt+del work on secondary screens? 2. Can the server and client be using different operating systems? 3. What's the difference between synergy and x2x, x2vnc, etc? 4. What does "Cannot initialize hook library" mean? 5. What security/encryption does synergy provide? 6. What should I call my screens in the configuration? 7. Why do my CapsLock and NumLock keys act funny? 8. Can synergy share the display in addition to the mouse and keyboard? 9. Can synergy do drag and drop between computers? 10. Do AltGr or Mode-Switch work? 11. Why isn't synergy ported to platform XYZ? 12. My client can't connect. What's wrong? 13. Linking fails on Solaris. What's wrong? 14. The screen saver never starts. Why not? 15. I can't switch screens anymore for no apparent reason. Why? Answers ------- 1. Why doesn't ctrl+alt+del work on secondary screens? Synergy isn't able to capture ctrl+alt+del on PC compatible systems because it's handled completely differently than other keystrokes. If you need to use ctrl+alt+del you'll have to keep your other keyboards handy just for that. Future versions may add support for or some equivalent to ctrl+alt+del. 2. Can the server and client be using different operating systems? Yes. The synergy network protocol is platform neutral so synergy doesn't care what operating systems are running on the server and clients. 3. What's the difference between synergy and x2x, x2vnc, etc? Unlike x2x, synergy supports any number of computers and it doesn't require X on Microsoft Windows platforms. It also has more advanced clipboard support and synchronizes screensavers. x2vnc is also limited to two computers, requires the separate vnc package, and is really only appropriate for using an X system to control a non-X system. However, the right tool for the job is whatever tool works best for you. 4. What does "Cannot initialize hook library" mean? This error can occur on a synergy server running on a Microsoft Windows operating system. It means that synergy is already running or possibly was not shut down properly. If it's running then first end the synergy task. If it's not then try logging off and back on or rebooting then starting synergy again. 5. What security/encryption does synergy provide? Synergy provides no built-in encryption or authentication. Given that, synergy should not be used on or over any untrusted network, especially the Internet. It's generally fine for home networks. Future versions may provide built-in encryption and authentication. Strong encryption and authentication is available through SSH (secure shell). Run the SSH daemon (i.e. server) on the same computer that you run the synergy server. It requires no special configuration to support synergy. On each synergy client system, run SSH with port forwarding: ssh -f -N -L 24800::24800 where is the name of the SSH/synergy server. Once ssh authenticates itself, start the synergy client normally except use `localhost' or `127.0.0.1' as the server's address. SSH will then encrypt all communication on behalf of synergy. Authentication is handled by the SSH authentication. A free implementation of SSH for Linux and many Unix systems called OpenSSH is available from http://www.openssh.com/. For Windows there's a port of OpenSSH using Cygwin (http://www.cygwin.com/). 6. What should I call my screens in the configuration? You can use any unique name in the configuration file for each screen but it's easiest to use the hostname of the computer. That's the computer name not including the domain. For example, a computer with the fully qualified domain name `xyz.foo.com' has the hostname `xyz'. There should also be an alias for `xyz' to `xyz.foo.com'. If you don't use the computer's hostname, you have to tell synergy the name of the screen using a command line option, or the startup dialog on Windows. 7. Why do my CapsLock and NumLock keys act funny? Some systems treat the Caps-Lock and Num-Lock keys differently than all the others. Whereas most keys report going down when physically pressed and going up when physically released, the Caps-Lock and Num-Lock keys report going down when being activated and going up when being deactivated. That is, when you press and release, say, Caps-Lock to activate it, it only reports going down, and when you press and release to deactivate it, it only reports going up. This confuses synergy. You can solve the problem by changing your configuration file. In the screens section, following each screen that has the problem, add either or both of these lines as appropriate: halfDuplexCapsLock = true halfDuplexNumLock = true Then restart synergy on the server. 8. Can synergy share the display in addition to the mouse and keyboard? No. Synergy is a KM solution not a KVM (keyboard, video, mouse) solution. However, future versions will probably support KVM. Hopefully, this will make synergy suitable for managing large numbers of headless servers. 9. Can synergy do drag and drop between computers? No. That's a very cool idea and it'll be explored. However, it's also clearly difficult and may take a long time to implement. 10. Does AltGr/Mode-Switch work? Sort of. Synergy sends the character you're trying to create from the server to the client. If the client can figure out how to create that character then it will do so, synthesizing whatever key events necessary. However, operating system differences can cause unexpected problems. Pressing either Ctrl key plus the left Alt key on Microsoft Windows means AltGr but on Unix that just means Ctrl and Alt are down. If you have a synergy server running on Windows and are having trouble with Ctrl+Alt_L = AltGr, try using the right Alt key as AltGr instead. 11. Why isn't synergy ported to platform XYZ? Probably because the developers don't have access to platform XYZ and/or are unfamiliar with development on XYZ. Also, synergy has inherently non-portable aspects so there's a not insignificant effort involved in porting. 12. My client can't connect. What's wrong? A common mistake when starting the client is to give the wrong server host name. The last synergyc command line option (Unix) or the "Server Host Name" edit field (Windows) should be the host name (or IP address) of the server *not* the client's host name. If you get the error "connection failed: cannot connect socket" followed by "the attempt to connect was forcefully rejected" or "connection refused" then the server isn't started, can't bind the address, or the client is connecting to the wrong host name/address or port. 13. Linking fails on Solaris. What's wrong? Did you add `--x-includes=/usr/openwin/include --x-libraries=/usr/openwin/lib' (without the linebreak) to the `configure' command line? Solaris puts the X11 includes and libraries in an unusual place and the above lets synergy find them. 14. The screen saver never starts. Why not? If the synergy server is on X Windows then the screen saver will not start while the mouse is on a client screen. This is a consequence of how X Windows, synergy and xscreensaver work. 15. I can't switch screens anymore for no apparent reason. Why? This sometimes happens but all the causes aren't yet known. One known cause is if the synergy server in running on Windows 95/98/Me and a 16-bit application is in the foreground when the screen saver starts. Windows fails to notify synergy that the screen saver has started in this situation (which is a bug in Windows, not synergy) and synergy may intercept some keyboard input and divert it to a client when the screen saver is running. As a result, it's possible for the server system to believe a key is pressed when it really isn't. Typically, it's the return key and simply tapping it will allow synergy to switch screens again. If this problem happens to you, try tapping the enter key to see if that solves the problem. If not, you can try running with debug logging (--debug DEBUG) and synergy will report exactly why it refuses to switch screens. If it claims a key is down then try tapping that key and see if that solves the problem.