如何通过PuTTY/MobaTerm实现Linux服务器及应用的双重自动登录（双ID不同）

Alright, let's walk through how to set up that two-step auto-login—first to your Linux system account, then to a separate application account—using PuTTY and MobaTerm. I’ve tackled this exact scenario a few times, so here’s the practical, step-by-step breakdown:

PuTTY Setup #

Step 1: Configure System Account Auto-Login #

• Open PuTTY, enter your Linux server’s IP/hostname and SSH port (default 22) in the Session tab.
• Navigate to Connection > Data: Fill in your system username in the "Auto-login username" field.
• Go to Connection > SSH > Auth: Click "Browse" to select your private key file (.ppk format) if you use key-based authentication—this skips manually entering the system password.
• Head back to Session, name your session (e.g., "Two-Step App Login") and click "Save" to store this base configuration.

Step 2: Automate the Application Account Switch #

Since the application account uses a different ID, we’ll use expect (install it on your server first with sudo apt install expect or sudo yum install expect) to handle the password prompt automatically.

• Create an expect script on your server, say switch_to_appuser.exp, with this content:

#!/usr/bin/expect -f
# Replace with your actual application account details
set app_user "appuser"
set app_pass "your_app_password"

# Wait for the system shell prompt, then initiate user switch
expect "$ "
send "su - $app_user\r"

# Wait for the password prompt and send the password
expect "Password:"
send "$app_pass\r"

# Keep the interactive session alive
interact

• Make the script executable: chmod +x switch_to_appuser.exp

• Edit your saved PuTTY session:

  • Go to Connection > SSH > Remote command, enter the full path to your script (e.g., /home/your_system_user/switch_to_appuser.exp)
  • Save the session again.

When you launch this PuTTY session, it’ll first log into your system account, then run the script to automatically switch to the application account.

Pro Tip: Storing passwords in plain text is risky. For better security, set up passwordless sudo access for your system user to the application account. Edit /etc/sudoers with visudo and add:
your_system_user ALL=(appuser) NOPASSWD: ALL
Then simplify the script to send sudo -u $app_user -i\r instead of su, and skip the password step entirely.

MobaTerm Setup #

MobaTerm’s built-in macro support makes this two-step login even more intuitive—no need for external scripts on the server.

Step 1: Create a Base SSH Session #

• Open MobaTerm, click Session > New session > SSH.
• Enter your server’s IP/hostname, SSH port, and system username.
• For key-based auth, go to the Advanced SSH settings tab, click "Browse" to select your private key.

Step 2: Add the Application Account Switch Macro #

• In the same SSH session window, go to the Macro tab.
• Check "Execute macro on startup", then click "Edit macro".
• Paste this script (adjust values to match your application account):

# Wait for the system shell prompt to appear
WaitForString "$ "
# Send command to switch to application account
SendCmd "su - appuser"
# Wait for the password prompt
WaitForString "Password:"
# Send the application account password
SendCmd "your_app_password"

• Save the macro, then save the session with a descriptive name.

Secure Alternative: Passwordless Switch #

Just like with PuTTY, set up passwordless sudo access for your system user to the application account. Then your macro can be simplified to:

WaitForString "$ "
SendCmd "sudo -u appuser -i"

No password handling needed, and it’s much more secure.

内容的提问来源于stack exchange，提问作者user870009