How to start SSHD in debug mode on Windows


In some cases your Aspera transfers may not work as expected due to issues with SSH starting up in Windows. It is therefore helpful to start SSHD in debug mode on your Aspera server to see if this is where the issues lie.


1. Stop the OpenSSH service.

Go to Control Panel > Administrative Tools > Services. Locate OpenSSH in the list of services, right click it and select Stop.

Alternatively, you can use the following commands to start or stop SSH:

sc stop sshd
sc start sshd

2. Open the Command Prompt as Administrator.

You can do this by right clicking the Command Prompt icon (from the Start menu) and selecting Run as administrator.

3. Run the following command, replacing svcAspera with the user who is authorized to run OpenSSH (this user was set when you installed your Aspera server):

runas /user:svcAspera cmd

If your service user is a domain user, use the format DOMAIN\User.

Enter the password for the user.

4. A new Command Prompt window will open with the title cmd (running as svcAspera).

Enter the following command to start SSHD in debug mode:

"C:\Program Files (x86)\Aspera\Enterprise Server\usr\sbin\sshd.exe" -dd -E C:\your_directory\sshd.log

The -E flag specifies where the log file should be written. Make sure the directory is writable for all users.

Additionally, you can use the -D flag to disable daemonization, and have logs displayed to standard out. CTRL-C would stop this SSHD, allowing the normal one to start.

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