Technical Notes

Using Debug Mode to Troubleshoot F-Secure SSH
Technical Note 1906
Last Reviewed 14-Jan-2004
Applies To
F-Secure SSH Client for Windows version 5.x
F-Secure SSH Server for Windows version 5.x
F-Secure SSH Client for UNIX version 5.x
F-Secure SSH Server for UNIX version 5.x
Summary

This technical note describes how to run F-Secure SSH in debug/verbose mode to get more information to troubleshoot general problems, especially authentication issues.

Running in Debug Mode

You can run both the server and client in debug mode.

Note: You must have administrative privileges to turn on debug mode on the server side.

Starting Debug Mode on the Client

On the F-Secure SSH Client, you may start in debug mode by running this command:

Starting Debug Mode on the Server

On the F-Secure SSH Server, you may start in debug mode by running this command:

Note: If you don't want to disturb your currently running ssh-daemon (daemon is the server process), it is usually better to run sshd2 in another port, like this:

This would run the server in verbose mode, in port 2222, and it would respond in that port.

Debug Levels

There are many levels of debugging. Level number 1 (example: ssh2 –d 1) gives you only very simple debug output, while level number 99, which is the maximum level of debug, gives you the most detailed debug output. Typically, level number 4 is enough to help you out.

Verbose mode (SSH run with -v option) is equal to debug-level 4. The –v option is available in F-Secure SSH Client and Server for UNIX, and Client for Windows. In F-Secure SSH Server for Windows, use the –d option.

To get the best results, run both the server and client in debug or verbose mode simultaneously. This way you can compare the debug output for both of them and better pinpoint your problem.

SSH debug output may look complicated, but simple problems may be easy to pinpoint.

Related Technical Notes

1928	Using Debug Mode to Troubleshoot Reflection or F-Secure SSH for Windows