PuTTY Terminal Login Guide

Complete tutorial for logging into remote systems via PuTTY

What is Terminal Login?

Terminal login refers to accessing a remote system's command-line interface through a text-based terminal emulator. With PuTTY, you can securely connect to remote servers (typically Linux/Unix systems) and execute commands as if you were sitting at the physical machine.

Common Use Cases:

  • Server administration and maintenance
  • Web application deployment and management
  • Database administration
  • System monitoring and troubleshooting
  • File management on remote systems
  • Software installation and configuration
  • Script execution and automation

Prerequisites

Before you begin, ensure you have:

  • ✅ PuTTY installed on your Windows computer
  • ✅ Server hostname or IP address
  • ✅ Valid username and password (or SSH key)
  • ✅ Network connectivity to the server
  • ✅ Firewall allows SSH connections (port 22 or custom port)

Step-by-Step Login Process

Step 1: Launch PuTTY

  • Double-click putty.exe to open
  • The PuTTY Configuration window appears
  • By default, you'll see the "Session" category selected

Step 2: Enter Hostname and Port

Hostname (or IP address):

  • Domain name: server.example.com
  • IPv4 address: 192.168.1.100
  • IPv6 address: 2001:db8::1

Port:

  • Default SSH port: 22
  • Custom port: Enter if server uses non-standard port (e.g., 2222)
  • Your server administrator will provide this if different from 22

Step 3: Select Connection Type

  • Select "SSH" from the connection type radio buttons
  • SSH (Secure Shell) encrypts all communication
  • Alternatives (Telnet, Raw, Rlogin) are rarely used and less secure

Step 4: Save Session (Optional but Recommended)

  1. In "Saved Sessions" field, enter a descriptive name:
    • Production Web Server
    • Dev-Database-MySQL
    • Client-Main-Server
  2. Click "Save"
  3. Next time, just double-click the saved session to connect quickly

Step 5: Open Connection

  1. Click the "Open" button
  2. A new terminal window opens
  3. On first connection, you'll see a security alert about the host key
  4. Click "Accept" to trust the server

Security Alert Explained: This warning appears because PuTTY hasn't seen this server before. It's verifying the server's identity. On subsequent connections to the same server, you won't see this warning.

Step 6: Enter Username

You'll see a prompt like:

login as: _

Enter your username and press Enter:

  • Common usernames: root, admin, ubuntu, ec2-user
  • Your organization may have specific usernames
  • Username is case-sensitive

Step 7: Enter Password

After entering username, you'll see:

user@server's password: _

Important notes:

  • Password characters will NOT be displayed as you type
  • No asterisks (*) or dots appear - this is normal security behavior
  • Type your password carefully and press Enter
  • Password is case-sensitive

Step 8: Successful Login

If login is successful, you'll see:

  • Welcome message or "Message of the Day" (MOTD)
  • System information (last login, uptime, etc.)
  • Command prompt waiting for input:
Last login: Mon Oct 14 10:23:45 2025 from 192.168.1.50

Welcome to Ubuntu 22.04 LTS

user@server:~$ _

You're now logged in and can execute commands!

SSH Key Login

Benefits of Key-Based Authentication

  • More secure than passwords
  • No need to type password each time
  • Enable automated scripts and deployments
  • Resistant to brute-force attacks

Using SSH Keys for Login

  1. Generate SSH key pair using PuTTYgen
    • Run puttygen.exe
    • Generate RSA or ED25519 key
    • Save private key (.ppk file)
    • Copy public key to server
  2. Configure PuTTY to use your key:
    • Connection → SSH → Auth → Credentials
    • Browse and select your .ppk file
    • Save session
  3. Connect:
    • Enter username (if not pre-configured)
    • Enter key passphrase (if you set one)
    • Automatic authentication - no password needed!

Session Management

Working in the Terminal

# Basic navigation
$ pwd                              # Print working directory
$ ls                               # List files
$ cd /var/www                      # Change directory

# File operations
$ cat file.txt                     # View file contents
$ nano file.txt                    # Edit file with nano
$ vim file.txt                     # Edit file with vim

# System commands
$ top                              # View processes
$ df -h                            # Disk usage
$ free -m                          # Memory usage
$ uptime                           # System uptime

# Package management (Ubuntu/Debian)
$ sudo apt update                  # Update package list
$ sudo apt upgrade                 # Upgrade packages

# Network commands
$ ping google.com                  # Test connectivity
$ netstat -tuln                    # List open ports
$ ifconfig                         # Network interfaces

Keeping Session Active

Prevent disconnection due to inactivity:

PuTTY Configuration:

  1. Connection category
  2. Set "Seconds between keepalives" to 60
  3. Enable "Enable TCP keepalives"
  4. Save session

Ending Your Session

# Proper logout commands
$ exit                             # Close connection
$ logout                           # Alternative to exit
# Or press Ctrl+D                 # End-of-file signal

Common Login Errors

Error: Network Error - Connection Timed Out

Causes:

  • Server is down or unreachable
  • Wrong IP address or hostname
  • Firewall blocking connection
  • Network connectivity issues

Solutions:

  1. Verify server is online: ping hostname
  2. Check IP address/hostname spelling
  3. Verify firewall allows SSH (port 22)
  4. Try from a different network

Error: Connection Refused

Causes:

  • SSH service not running on server
  • Wrong port number
  • Firewall blocking specific port

Solutions:

  1. Verify SSH service is running (check with server admin)
  2. Confirm correct port number
  3. Check server firewall rules

Error: Access Denied / Login Incorrect

Causes:

  • Wrong username or password
  • Account locked or disabled
  • Wrong SSH key
  • Too many failed attempts (IP blocked)

Solutions:

  1. Double-check username and password (case-sensitive)
  2. Verify account is active
  3. Contact administrator if locked out
  4. Wait 10-15 minutes if temporarily blocked

Error: Server's Host Key Did Not Match

Causes:

  • Server was rebuilt or reinstalled
  • Possible man-in-the-middle attack
  • Changed SSH host keys

Solutions:

  1. If you know server was rebuilt, click "Update" to accept new key
  2. Or delete old host key from Windows Registry
  3. If unexpected, contact server administrator before proceeding

Advanced Login Options

Auto-login Username

Skip the "login as:" prompt:

  • Connection → Data
  • Enter username in "Auto-login username"
  • Save session

Terminal Settings

Customize your terminal experience:

  • Terminal → Bell: Configure alert sounds
  • Window → Appearance: Change font and colors
  • Window → Lines of scrollback: Increase to 20000+
  • Window → Translation: Set to UTF-8 for Unicode support

Security Best Practices

  • ✅ Always use SSH (never Telnet)
  • ✅ Use SSH keys instead of passwords when possible
  • ✅ Use strong, unique passwords (12+ characters)
  • ✅ Verify host key on first connection
  • ✅ Keep PuTTY updated to latest version
  • ✅ Don't ignore security warnings
  • ✅ Log out properly when done (use exit)
  • ✅ Enable keepalives for long sessions
  • ❌ Don't save passwords in unsecured locations
  • ❌ Don't ignore host key changes
  • ❌ Don't use root account for daily tasks
  • ❌ Don't share your login credentials

Quick Reference

ActionCommand/Method
LoginEnter username and password
Logoutexit or logout or Ctrl+D
Clear screenclear or Ctrl+L
Interrupt commandCtrl+C
Copy textSelect with mouse
Paste textRight-click
Scroll up/downMouse wheel or scrollbar

Related Resources

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