Serverless LAN Chat

KouChat icon

Frequently Asked Questions

1. What is Kou?

Kou is a cow character I’ve made. You can see Kou at the Super Kou project page. Kou is pronounced kind of like the way cows say moooo, but it’s OK to just call him Cow.

2. KouChat crashed, doesn’t connect, or behaves strangely.

First, make sure you are using the latest version. When you do, the easiest way to find the problem is for you to run KouChat from the command line, like this:

java -jar kouchat-x.x.x.jar

If you see any errors, write them down. If nothing of interest shows up, then you can try enabling debug output by running KouChat like this:

java -jar kouchat-x.x.x.jar --debug

Please check the other pages for help as well. When you can reproduce the problem, report it as an issue with as many details as possible.

3. I minimized KouChat, and it’s not visible on the taskbar anymore.

Have a look in the system tray. There should be a small black and white icon there with a cow pattern. Click on it to open KouChat again. If you don’t find the icon, it might be hidden. Check the system tray settings to make it visible.

4. How do I change my nick name?

Open the Tools menu, and choose Settings.

5. How do I send files?

Right click on a user in the user list on the right side, and choose Send file. You can also drag and drop a file on a user in the list, or in a private chat window.

6. How do I open a private chat?

You can double click on a user in the user list, or you can right click on a user in the user list and choose Private chat.

7. The file chooser is horribly slow in Windows XP.

This is a Java bug, see bug 6578753. As a workaround you can move any zip-files lying on the desktop to some other folder.

8. How do I enable console mode?

Run KouChat like this from the command line:

java -jar kouchat-x.x.x.jar --console

Type /help for a list of commands you can use while in console mode.

9. How come some messages don’t show up in other clients?

That’s probably because of packet loss. KouChat uses the UDP protocol, which does not resend lost packets. Packet loss is usually not a problem in wired networks, but wireless networks might have some loss.

10. Where do the log files go?

The logs are put in .kouchat/logs/ in your home folder, sorted by date and time of creation.


  • Windows XP - C:\Documents and Settings\Your Username\.kouchat\logs\
  • Windows 7 - C:\Users\Your Username\.kouchat\logs\
  • Linux - /home/username/.kouchat/logs/

11. Why do non-ascii characters look wrong when using console mode in Windows?

That’s because the command line in Windows uses the old DOS character set instead of the normal Windows character set. A common DOS character set is cp850 and a common Windows character set is cp1252. I’ve found 2 ways to work around this problem:

  1. Change the character set on the command line to match the character set used by Windows. If your Windows character set is cp1252, just run the command ‘chcp 1252’ before starting KouChat. For this to work you need a console font which supports the chosen character set, like Lucida Console.
  2. Change the character set used by Java to match the character set on the command line. You can get the current command line character set by running the command ‘chcp’. Then use the character set number when starting KouChat: java -Dfile.encoding=850 -jar kouchat-x.x.x.jar --console

12. Why don’t I have the Nimbus look and feel?

Nimbus is a new look and feel that comes with Java 6 update 10 and newer. If you don’t see Nimbus in the list, then you need to update to the newest version of Java.

13. Where can I find an icon to use for shortcuts?

There is an icon available inside kouchat-x.x.x.jar, in two different formats:

  • kou_shortcut.ico
  • kou_shortcut.png

To get these, you can just open the jar file in a decompression utility like WinZip or 7-Zip.

14. Which smileys are available?

There are 11 different smileys available, for different needs. Try them :)

  • :)
  • :(
  • :p
  • :D
  • ;)
  • :O
  • :@
  • :S
  • ;(
  • :$
  • 8)

15. Why is the window sometimes only maximized vertically or horizontally after being unhidden from the system tray?

I don’t know! But I’m unable to reproduce the problem using early versions of Java 7, so I’m guessing it’s not my bug ;)

16. I have a great suggestion for a new feature. What do I do?

Cool :) Just register the suggestion in the issue tracker with “Feature request” in the title.

17. KouChat uses the wrong network interface. How can I switch?

Typical use cases include:

  • You want to connect to the wired network by default, but KouChat keeps connecting to the wireless network.
  • KouChat connects using a “fake” network interface that ships with virtualization software like VMware and Virtual Box.

You can override the network interface chosen by KouChat in the settings. Choose one in the list and click OK to switch. Tip: hold the mouse cursor over each of the items in the drop down list for more details about the network interface, if available.

18. How can I get KouChat to open in front of other applications after being unhidden from the system tray in KDE?

The window manager in KDE is usually configured with a feature called Focus stealing prevention. This feature keeps new windows from opening in front and stealing focus. However, when unhiding KouChat from the system tray it’s usually because one wants to interact with the window, and the focus stealing prevention gets in the way.

It can be disabled globally or per application. Here is how to disable for KouChat only:

Right click on the title bar of the KouChat window, then click on Advanced/Special Application Settings. Go to the rightmost tab, called something like Workarounds or Appearance & Fixes (depends on the version of KDE). Enable the checkbox on Focus stealing prevention, and set it to Force and None in the 2 drop down lists, then click OK to save.

19. Which ports do I need to have open in the firewall?

If your firewall is blocking network traffic then KouChat will show the text “Not connected” in the title bar. The following ports needs to be open for everything to work correctly:

  • Main chat: UDP port 40556
  • Private chat: UDP port 40656 (increased by one for each running instance)
  • File transfer: TCP port 40756
  • Network detection: UDP port 50050

20. The KouChat window is invisible over Remote Desktop. How can I fix it?

This happens on some configurations. Try adding ‘-Dsun.java2d.noddraw=true’ to the shortcut command when starting KouChat, like this:

javaw -Dsun.java2d.noddraw=true -jar kouchat-x.x.x.jar

21. How can I start KouChat minimized?

Note: only available in the development version of KouChat 1.3.0.

Add the startup argument ‘--minimized’ to the shortcut or script that starts KouChat, like this:

java -jar kouchat-x.x.x.jar --minimized

Put the shortcut or script in the startup/autostart folder of your operating system to run automatically on boot.

22. KouChat stopped connecting after upgrading to Java 7u71. How can I fix it?

This is a new bug in Java 7u71 that appears when IPv6 is disabled. Details on the bug can be read here: JDK-6458027

If you can’t enable IPv6 then you can tell Java to prefer IPv4 as a workaround. Add ‘-Djava.net.preferIPv4Stack=true’ to the shortcut command when starting KouChat, like this:

java -Djava.net.preferIPv4Stack=true -jar kouchat-x.x.x.jar

23. Why doesn’t the system tray icon respond to clicks in KDE 5?

Known issue with Java applications in KDE 5. As a workaround you can disable system tray integration in KouChat 1.3.0.

You can follow the progress here: issue 19.