Synergy client won't connect, despite open port?

Question

I want to use a Debian KDE desktop computer (network name bradbury) as the server, and a Windows 7 laptop (network name Clarke) as the client. I have used this setup before without problems, but then there was a Fedora on the server. Now the client only gives

WARNING: failed to connect to server: Timed out. 

What I did:

• installed Synergy from the repository
• saved a config file under /etc/synergy.conf

    section: screens
        bradbury:
        Clarke:
    end

    section:aliases
      Clarke:
        192.168.178.39
    end

    section: links
        bradbury:
            down = Clarke
        Clarke:
            up = bradbury
    end

• opened port 24800 (at least I think I did, this is the first time I have used iptables)

sudo iptables -A INPUT -p tcp --dport 24800 -j ACCEPT
sudo iptables -A OUTPUT -p tcp --dport 24800 -j ACCEPT

It seems that the port is indeed open.

rumtscho@bradbury:~$ netstat -an |grep 24800 |grep -i listen
tcp        0      0 0.0.0.0:24800           0.0.0.0:*               LISTEN   

• checked on the router that my computer's IP is indeed 192.168.187.22, and the laptop's IP is 192.168.178.39
• started synergy

rumtscho@bradbury:~$ synergys -f -n bradbury
2014-03-21T11:50:29 INFO: Synergy 1.3.8 Server on Linux 3.2.0-4-amd64 #1 SMP Debian 3.2.54-2 x86_64
        /tmp/buildd/synergy-1.3.8/src/cmd/synergys/synergys.cpp,1098
2014-03-21T11:50:29 DEBUG: opening configuration "/home/rumtscho/.synergy.conf"
        /tmp/buildd/synergy-1.3.8/src/cmd/synergys/synergys.cpp,1113
2014-03-21T11:50:29 DEBUG: cannot open configuration "/home/rumtscho/.synergy.conf"
        /tmp/buildd/synergy-1.3.8/src/cmd/synergys/synergys.cpp,1120
2014-03-21T11:50:29 DEBUG: opening configuration "/etc/synergy.conf"
        /tmp/buildd/synergy-1.3.8/src/cmd/synergys/synergys.cpp,1113
2014-03-21T11:50:29 DEBUG: configuration read successfully
        /tmp/buildd/synergy-1.3.8/src/cmd/synergys/synergys.cpp,1124
2014-03-21T11:50:29 DEBUG: XOpenDisplay(":0")
        /tmp/buildd/synergy-1.3.8/src/lib/platform/CXWindowsScreen.cpp,901
2014-03-21T11:50:30 DEBUG: xscreensaver window: 0x00000000
        /tmp/buildd/synergy-1.3.8/src/lib/platform/CXWindowsScreenSaver.cpp,342
2014-03-21T11:50:30 DEBUG: screen shape: 0,0 5120x1440 (xinerama)
        /tmp/buildd/synergy-1.3.8/src/lib/platform/CXWindowsScreen.cpp,136
2014-03-21T11:50:30 DEBUG: window is 0x04c00004
        /tmp/buildd/synergy-1.3.8/src/lib/platform/CXWindowsScreen.cpp,137
2014-03-21T11:50:30 DEBUG: opened display
        /tmp/buildd/synergy-1.3.8/src/lib/synergy/CScreen.cpp,41
2014-03-21T11:50:30 DEBUG: registered hotkey ScrollLock (id=ef14 mask=0000) as id=1
        /tmp/buildd/synergy-1.3.8/src/lib/platform/CXWindowsScreen.cpp,729
2014-03-21T11:50:30 NOTE: started server
        /tmp/buildd/synergy-1.3.8/src/cmd/synergys/synergys.cpp,515
2014-03-21T11:50:30 INFO: screen "bradbury" shape changed
        /tmp/buildd/synergy-1.3.8/src/lib/server/CServer.cpp,1194

But the client still won't connect.

Answer 1

• You have to run the same version of synergy for both version.

• Check the hostname.

• Check if you do not have any firewall on windows/linux that is generating issues.
• Change the port 24800 by 8081. That works for me.
• Remember both have to listen the same port.

Good luck!

Answer 2

I solved adding the port with this command in ubuntu:

(a bit different from previous posts)

iptables -I INPUT 1 -p tcp --dport 24800 -j ACCEPT

Answer 3

In linux, I needed to use this command like described earlier:

sudo iptables -A INPUT -p tcp --dport 24800 -j ACCEPT
sudo iptables -A OUTPUT -p tcp --dport 24800 -j ACCEPT

I also added the computer name (client and server) in configuration, exact same names at both of them. (Ex: computer-client, computer-server).

Answer 4

Except for having the correct iptables rules mentioned all around here, be sure you apply the rules in the correct order within your iptables configuration as well. Apply them BEFORE the rule that drops/rejects the packets. That was something I needed to figure out :-).