Linux – Synergy client won’t connect, despite open port

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.