Troubleshooting SSH Connection Issues on Ubuntu 24.04 After Using VS-Code Remote-SSH

Symptoms

Inability to SSH into a remote Ubuntu 24.04 server after using VS-Code Remote-SSH, leading to frequent disconnections.

Environment

Ubuntu 24.04 server, VS-Code with Remote-SSH extension, SSH client on local machine.

Most Likely Causes

Possible SSH configuration issues, network interruptions, or VS-Code settings affecting the SSH connection.

What to Check First

1. Verify network connectivity to the server.
2. Check the SSH service status on the server.
3. Review VS-Code Remote-SSH settings.

Fix Steps

1. Check network connectivity to the remote server.

   Use the ping command to ensure the server is reachable.

   Example pattern only. Adjust for your environment before running.

   ping <server-ip>

2. Verify the SSH service is running on the remote server.

   Log into the server console or use another method to check the SSH service status.

   Safe to run: read-only

   sudo systemctl status ssh

3. Check the SSH configuration file for any misconfigurations.

   Open the SSH configuration file and review for any unusual settings.

   Safe to run: read-only

   sudo nano /etc/ssh/sshd_config

4. Restart the SSH service to apply any changes made.

   Restart the SSH service to ensure it is running with the latest configuration.

   Changes system state: review before running

   sudo systemctl restart ssh

5. Adjust VS-Code Remote-SSH settings to prevent disconnections.

   Modify the settings in VS-Code to increase the timeout duration.

   Safe to run: read-only

   Open VS-Code settings and search for 'Remote.SSH: Connect Timeout' and increase the value.

Validation

• Attempt to SSH into the server from the terminal after performing the steps.
• Monitor VS-Code for stable connectivity.

Logs to Check

• /var/log/auth.log for SSH login attempts and errors.
• /var/log/syslog for any related system messages.

Rollback and Escalation

• Revert any changes made to the SSH configuration if connectivity issues arise.

Escalate When

• If SSH service fails to start after configuration changes.
• Persistent connectivity issues despite following troubleshooting steps.

Edge Cases

• Check for firewall rules blocking SSH connections.
• Verify if the server's IP has changed.

Notes from the Field

• Ensure that the local SSH client is updated to avoid compatibility issues.
• Consider using a different SSH client if problems persist.