Frequently Asked Questions

Find quick answers to common PuTTY questions and issues

Connection Issues

Why can't I connect to my server?

Check that: 1) The server is running and accessible, 2) You're using the correct hostname/IP and port, 3) Your firewall isn't blocking the connection, 4) The SSH service is running on the server (usually port 22).

What does 'Connection refused' mean?

This usually means the server is not running an SSH service on the specified port, or a firewall is blocking the connection. Verify the server is running and the port is correct.

I get 'Network error: Connection timed out'

This typically indicates a network connectivity issue. Check your internet connection, verify the server address, and ensure no firewall is blocking the connection.

The connection keeps dropping

Enable keepalives in PuTTY: Go to Connection settings and set 'Seconds between keepalives' to 30. This prevents idle timeouts.

Authentication

My password authentication isn't working

Ensure you're entering the correct username and password. Some servers disable password authentication in favor of key-based auth. Check with your system administrator.

How do I use SSH keys with PuTTY?

Generate keys with PuTTYgen, save the public key to your server's ~/.ssh/authorized_keys file, and load the private key in PuTTY under SSH > Auth > Private key file.

PuTTY won't accept my OpenSSH private key

OpenSSH keys must be converted to PuTTY format (.ppk). Use PuTTYgen: load your OpenSSH key, then save it as a .ppk file.

I get 'Server refused our key'

Check that: 1) The public key is correctly added to ~/.ssh/authorized_keys on the server, 2) The permissions are correct (600 for the file, 700 for ~/.ssh), 3) You're using the right private key file.

Terminal Issues

Characters are displaying incorrectly

Go to Window > Translation and try different character set options. UTF-8 works for most modern systems. Also check your terminal font supports the characters you need.

Colors aren't showing properly

Enable ANSI colors: Go to Window > Colours and check 'Allow terminal to use xterm 256-colour mode'. Some applications may need specific terminal type settings.

The terminal window is too small

Resize the window or set default size in Window > Columns/Rows. You can also save the session to remember your preferred size.

Backspace and Delete keys don't work properly

Go to Terminal > Keyboard and try different settings for 'Backspace key' and 'Delete key'. The correct setting depends on your server configuration.

File Transfer

How do I transfer files with PuTTY?

PuTTY itself doesn't transfer files. Use PSCP for command-line transfers or PSFTP for interactive file transfer. Both are included with PuTTY.

PSCP says 'command not found'

PSCP is a separate executable. Download it from the same place you got PuTTY, or use the installer which includes all tools.

File transfers are very slow

Try enabling compression in the SSH connection settings, or use a different cipher. Network conditions and server load also affect transfer speed.

Can I transfer entire directories?

Yes, use PSCP with the -r (recursive) option: 'pscp -r local_directory user@server:remote_path'

Configuration

How do I save my connection settings?

Enter your connection details, type a name in 'Saved Sessions', and click Save. You can then load these settings anytime by selecting the session name.

Can I export my PuTTY settings?

PuTTY stores settings in the Windows registry. You can export the HKEY_CURRENT_USER\Software\SimonTatham\PuTTY key to save your settings.

How do I set up port forwarding?

Go to SSH > Tunnels, enter source port, destination (host:port), select Local or Remote, and click Add. Don't forget to save the session.

PuTTY starts too slowly

Disable unnecessary features like host key checking prompts, or use session files instead of registry storage for faster startup.

Security

Is PuTTY secure?

Yes, PuTTY implements strong encryption and is regularly updated. Always download from the official source and keep it updated.

Should I accept unknown host keys?

Only if you can verify the key fingerprint through a secure channel. Unknown host keys could indicate a man-in-the-middle attack.

What encryption does PuTTY use?

PuTTY supports various encryption algorithms including AES, ChaCha20, and 3DES. Modern versions default to secure algorithms like AES-256.

How do I verify a server's fingerprint?

Compare the fingerprint shown by PuTTY with the one provided by your system administrator through a secure channel (not email).

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Quick Tips

Before Asking for Help

  • • Check this FAQ first
  • • Try the official documentation
  • • Note exact error messages
  • • Test with a simple connection
  • • Check your network connectivity

When Reporting Issues

  • • Include PuTTY version number
  • • Describe your operating system
  • • Provide exact error messages
  • • Explain what you were trying to do
  • • Mention what you've already tried
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