This guide explains how to install PuTTY on Ubuntu 22.04 with a single apt command that also pulls the putty‑tools package for useful command‑line helpers like plink. It walks readers through verifying the installation by running putty -v and checking that the GUI launches from either the terminal or the applications menu. The tutorial then covers converting an OpenSSH private key to PuTTY’s .ppk format with puttygen, configuring the key in PuTTY’s Auth pane, and setting an auto‑login username for smoother use. Finally, it lists common troubleshooting steps—such as checking firewall rules, ensuring correct permissions on authorized_keys, and reinstalling if the binary is missing—to help users resolve typical connection or authentication hiccups.

Installing PuTTY SSH Client on Ubuntu 22.04 LTS

Ubuntu users often default to OpenSSH, but the old‑school PuTTY still has a place—especially if you’re dealing with Windows‑style .ppk keys or just like its menu‑driven interface. This quick guide shows how to drop it into your system, set up key authentication, and connect without tripping over common snags.

Installing PuTTY SSH Client on Ubuntu 22.04 LTS

1. Open a terminal window (Ctrl+Alt+T).
   The package manager lives there; no GUI needed.

2. Update the package list: sudo apt update
   Keeps your repository cache fresh so you get the latest PuTTY build.

3. Install PuTTY and its companion utilities: sudo apt install putty putty-tools
   putty-tools gives you plink, a lightweight command‑line alternative that can be handy in scripts.

After the install finishes, typing putty should launch the GUI. If it doesn’t, make sure your $PATH includes /usr/bin; you can check with which putty.

Verifying the installation

Run putty -v. The output will show the version number and build date. A quick sanity check: try launching PuTTY from the Applications menu; if it pops up, the install succeeded.

If you get “command not found,” double‑check that your user’s environment isn’t missing /usr/bin. In a rare case after a system upgrade, the symlink to putty can vanish—re‑installing fixes that.

Configuring SSH key authentication

PuTTY expects keys in PuTTY’s own format (.ppk). Most Linux users generate OpenSSH keys (id_rsa). Converting is painless:

1. Generate or locate your private key: ssh-keygen -t ed25519 -C "user@machine"
   Ed25519 is stronger and faster than RSA.

2. Convert it to PuTTY format: puttygen ~/.ssh/id_ed25519 -O private -o ~/.ssh/id_ed25519.ppk
   PuTTY won’t read raw OpenSSH keys directly; the converter writes a compatible binary file.

3. In PuTTY’s “Connection → SSH → Auth” pane, browse to ~/.ssh/id_ed25519.ppk.
   This tells PuTTY which private key to present when authenticating.

If you’re using an existing .ppk, skip steps 1–2 and just load it into the Auth section.

Connecting to a remote host

Open PuTTY, then:

• In “Host Name (or IP address)”, type user@192.168.1.10 (replace with your server’s details).
  This is the actual SSH target.

• Under “Connection → Data”, set “Auto-login username” to user.
  Avoids being prompted for the username after launch; handy in scripts that call PuTTY from the command line.

• Click “Open”. The first time you connect, a security alert will pop up showing the server’s fingerprint. Verify it against what your admin sent you; otherwise, close and abort to avoid a man‑in‑the‑middle.

Once connected, you’ll see a familiar terminal prompt. You’re good to go.

Troubleshooting common hiccups

• PuTTY hangs or shows “Connection refused” Check that the remote machine’s firewall allows SSH on port 22 and that the service is running (sudo systemctl status ssh). If you recently switched from OpenSSH to sshd, ensure the config file points to the right key files.

• Authentication fails with “Permission denied (publickey)”
  Confirm that your public key has been added to ~/.ssh/authorized_keys on the server and that permissions are correct (chmod 700 ~/.ssh; chmod 600 ~/.ssh/authorized_keys). Also, make sure PuTTY is loading the right .ppk.

• PuTTY doesn’t start from the terminal
  The command might be aliased or missing. Try which putty to locate it, or run /usr/bin/putty. If you see “command not found,” reinstall: sudo apt install --reinstall putty.

Using PuTTY for SSH connections on Linux

While Ubuntu ships with OpenSSH client tools that are great for the command line, PuTTY shines when you need a GUI or Windows‑style key management. It’s also handy if your workflow involves scripts that spawn GUI sessions or when you’re migrating from a Windows environment and don’t want to rewrite scripts.