Technical Tip: How to create a log file of a session using PuTTY

[kraturi_FTNT]

Description

This article describes how to configure PuTTY to create a log file of a session.

This is useful in cases where Fortinet support requests the output of commands, or there is a need to ensure the output of all troubleshooting commands will be collected and saved. 

Scope

FortiGate.

Solution

1. Double-click the PuTTY icon to launch the application.
   
   

2. On the left menu Session -> Click Logging
   The logging settings are listed here on the right. To save a log file to the desktop:
   Select Printable output - this option will not log keystrokes, such as backspace, for example.
   Enable Always append to the end of the log file.
   Enable Flush log file frequently.

3. Under the Log file name, select 'Browse' and save it on the local disk (avoid saving over a network remote drive).
   
   
4. On the left menu Window, increase the terminal width to 237 columns as it may add line breaks that may interfere with the log analysis. 
   Optionally, increase the Lines of scrollback to keep more lines being displayed. Note that all content will still be saved into the file. 
   
   
   

5.  On the left menu select Connection -> Enable the keepalive every 2 seconds.
   
   
   
   

6. On the left menu Session again, enter a chosen name under 'Saved Sessions' and select save to save and avoid having to re-configure it every time Putty is opened. 
   Tip: Typing 'Default Settings' will ensure the settings are saved as the default, will be loaded every time Putty is launched.

 

7. Under Connection type, select SSH, Serial or the method being used, and then select 'Open' to open the connection.
   
   
8. Enter the username, then press <Enter>
   
   

9. Enter the password associated with the user, then press <Enter>.
   
   

10. From this point and onwards, connection should be established, while all output will be saved into a log file.
    Run any commands necessary, and attach the saved file in the FortiCare Support ticket for TAC review.
    
    

Related Video:

Linux and macOS devices logging SSH sessions:

On these platforms, PuTTY is not widely used. It is common to instead call a built-in SSH client directly from a terminal window. The 'tee' command can be used in conjunction with SSH to log session output to a file. See Technical Tip: Logging FortiGate administrative SSH sessions from Linux/MacOS endpoints.