PuTTY Configuration Guide

PuTTY configuration covers everything from saving named session profiles to fine-tuning your putty login credentials, SSH authentication method, terminal colors, and keepalive intervals. This guide walks through the most important settings panel by panel, written for professional use.

Saving and Loading Sessions

PuTTY stores named session profiles in the Windows registry at HKCU\Software\SimonTatham\PuTTY\Sessions. Each saved session stores all configuration options independently.

  1. Open PuTTY. In the Session category, enter your server's hostname or IP address and the port (default: 22).
  2. Type a descriptive name in the Saved Sessions field (e.g., production-web-01).
  3. Configure any additional settings (see sections below).
  4. Click Save. The session now appears in the list for one-click future access.
  5. To connect, select the session name and click Open.

Session Category – Connection Settings

SettingLocationRecommendation
Connection typeSessionSet to SSH for secure connections.
PortSessionDefault is 22. Change if the server uses a non-standard port.
Close window on exitSessionSet to 'Only on clean exit' to keep the window open on errors.
Seconds between keepalivesConnectionSet to 30–60 to prevent idle timeout disconnections.
Enable TCP keepalivesConnectionEnable to prevent NAT firewalls from dropping idle connections.
Auto-login usernameConnection > DataPre-fill to avoid typing username every connection.

Terminal Appearance – Fonts and Colors

Changing the Font

  1. In the left panel, navigate to Window → Appearance.
  2. Click Change next to Font used in the terminal window.
  3. Recommended fonts: Consolas 11pt, Cascadia Mono 11pt, or Courier New 10pt.

Configuring Colors

  1. Navigate to Window → Colours.
  2. Select a color from the list (e.g., Default Background) and click Modify.
  3. Set the RGB values. Popular dark theme values:
# Dark Professional Theme Colors (RGB values)
Default Background:  R:15   G:17   B:23   (#0f1117)
Default Foreground:  R:226  G:232  B:240  (#e2e8f0)
ANSI Green:          R:0    G:200  B:150  (#00c896)
ANSI Cyan:           R:0    G:212  B:255  (#00d4ff)
ANSI Yellow:         R:255  G:213  B:100  (#ffd564)

SSH Key Authentication

  1. Navigate to Connection → SSH → Auth → Credentials.
  2. Click Browse next to Private key file for authentication.
  3. Select your .ppk private key file (generated with PuTTYgen).
  4. Save the session — the key path is stored with the session profile.

SSH Keepalives and Timeout Prevention

Corporate firewalls and NAT devices often terminate idle SSH connections. Configure keepalives to prevent this:

  1. Navigate to Connection.
  2. Set Seconds between keepalives to 30.
  3. Check Enable TCP keepalives (SO_KEEPALIVE option).

X11 Forwarding

To run graphical Linux applications over the SSH connection, enable X11 forwarding. You will also need an X server on Windows such as VcXsrv:

  1. Navigate to Connection → SSH → X11.
  2. Check Enable X11 forwarding.
  3. Set X display location to localhost:0.

Session Logging

  1. Navigate to Session → Logging.
  2. Select All session output or SSH packets and raw data (for debugging).
  3. Set a log file path such as C:\Logs\putty_%Y%M%D_%H%M%S.log (time-stamped).

Proxy Configuration

For environments behind a corporate proxy:

  1. Navigate to Connection → Proxy.
  2. Select the proxy type: HTTP, SOCKS5, or Telnet.
  3. Enter the proxy host, port, and credentials if required.

Backing Up PuTTY Sessions

Export all saved sessions from the registry to a portable .reg file:

# Export (run in cmd.exe or PowerShell)
reg export "HKCUSoftwareSimonTatham" PuTTY-backup.reg /y

# Import on another machine
reg import PuTTY-backup.reg
Portable Sessions: If you use PuTTY portable mode with a putty.ini file, sessions are stored in that file instead of the registry. Simply copy the file to move sessions between machines.