Network Troubleshooting Quiz

Network Troubleshooting

• Connectivity issues involve ping tests using tools like Wireshark
• Firewall policies, port blocking, and VPN connectivity issues are also addressed
• Website access problems are diagnosed through ping tests to verify IP connectivity, DNS resolution checks, and firewall checks.
• TCPing tests are used to see if website ports are open.
• Website access is confirmed or issues are identified and resolved with different browsers or by disabling extensions.
• Intermittent connectivity issues are troubleshooted through Gateway ping tests, network cable/Wi-Fi signal checks and IP conflict verification using arp -a

VPN Connectivity Issues

• Internal resource access problems are addressed by checking VPN IP addresses, pinging internal resources verifying firewall policy and DNS settings.
• Route table is checked to see if routes to internal subnets are present.

Network Latency Issues

• High latency issues in network applications are identified by ping tests.
• Traceroutes help pinpoint points of latency in the network path.
• TCPing specific ports is used to identify any delays in connection establishment.
• Bandwidth testing and QoS settings are verified.

File/Folder Permission Issues

• File server reachability is verified through ping tests.
• Port 445 (SMB) is checked for accessibility.
• DNS resolution to hostname is checked.
• User permissions for the network share are confirmed.
• File/folder ownership, permissions and encryption are checked if access to file/folder is restricted.

Slow Network Speeds

• Ping tests to confirm packet loss or high latency are performed.
• Network bandwidth usage is checked for bottlenecks.
• QoS settings and throttling policies are examined.
• Latency is measured using tcping to services/websites.
• Device network adapter settings are verified.

User Can't Connect to Remote Desktop via VPN

• Connectivity to the remote machine’s IP address is checked
• Firewall policy is confirmed to allow RDP (usually on port 3389) through the VPN.
• tcping test on port 3389 is used to confirm that the RDP port is open.
• Correct routing between the VPN subnet and internal network is confirmed.
• User has the correct permission to access remote desktop

Network Device Inaccessibility

• Device IP is confirmed to be reachable on the network.
• TCPing tests are performed on the management port.
• Firewall rules are checked to verify if traffic from the monitoring server to devices is allowed.
• SNMP/SSH settings are checked for enabling.
• Firmware is verified to be up-to-date.

Application Crashes or Freezes

• Application updates are checked for updates.
• Temporary files are cleared.
• Logs in Event viewer are checked for error codes.
• Applications are run in compatibility mode with older OS versions if necessary.
• Corrupted files are replaced by reinstalling the application.

Blue Screen of Death (BSOD)

• BSOD error code is recorded.
• Recent driver, hardware or update installations are checked.
• System files are scanned and repaired using the command sfc /scannow in the command prompt.
• Drivers, especially graphics and chipset drivers, are updated.
• Windows memory diagnostic is run to check for faulty RAM.

Printer Not Responding

• Printer connection is checked
• Print Spooler service is restarted
• Printer drivers are updated.
• Default printer is verified to be correct.
• Printing from a different application is tested.

Network Connectivity Issues

• Physical connections to the network cable or Wi-Fi signal strength are checked.
• Network troubleshooter is run for automatic diagnostics.
• DNS is flushed.
• Firewall is disabled temporarily to see if blocking the connection.
• Testing with another device verifies the network and user's device compatibility for connection problems.

Account Lockout or Login Issues

• Checking password expiry, especially in domain environments.
• Resetting a user’s password if they are locked out
• Checking logs in Event Viewer for login attempts.
• Verifying Network Connection if login requires domain authentication
• Clearing Cached Credentials if there are conflicting credentials

File or Folder Permission Issues

• Checking File Properties and verifying permissions under Security.
• Taking ownership of the files or folders if access is restricted.
• Adjusting permissions to allow user full access if necessary.
• Checking for encryption and ensuring the user has the correct encryption key.
• Checking Network drive permissions.

Firewall and Security Troubleshooting

• Firewall rules, access issues, and threat logs are addressed.
• FortiClient VPN troubleshooting is mentioned.

Application Traffic Blocked

• Recent changes to firewall rules are reviewed.
• Logs are analyzed to check if application traffic is denied.
• Application ports are verified to ensure firewall rules permit application usage
• Temporary rules are created to verify if traffic flows correctly.

Unauthorized Access Attempts

• Source IP address is identified.
• Firewall rules are created to block incoming traffic from the suspicious IP.
• Existing vulnerabilities are checked
• Geo-IP blocking is enabled if needed.
• Continued monitoring of logs is performed to identify new access attempts.

FortiClient VPN Problems

• VPN gateway reachability is confirmed through ping tests.
• Required VPN ports are checked (e.g., 443, 500, 4500).
• VPN credentials are confirmed to be correct
• Firewall policy allowing VPN traffic is confirmed.
• tcping tests are performed on the VPN port to confirm connectivity to the gateway.

Remote User Cannot Connect to VPN

• Configurations for VPN server address, username and password are verified.
• User VPN permissions are verified.
• Necessary firewall ports are confirmed to be open (example 443 or 500/4500 for IPsec).
• Logs are reviewed for any errors.
• Latest FortiClient version is verified

Internal Service Unreachable

• Recent rule changes are reviewed to see if they are causing an issue.
• Required ports for the internal service are confirmed to be allowed.
• Network segmentation is confirmed and restrictions, if any, are addressed.
• Internal traffic is tested to check service reachability.

High Traffic from Unusual IP

• Source IP address details are identified and checked for malicious sources.
• Temporary block rule for the IP address is created.
• Traffic patterns are analyzed.
• Internal device compromises and unusual traffic are checked.
• Permanent block of the IP is implemented if necessary.

New Server Failing to Connect to the Internet

• IP and Gateway settings are checked.
• Outbound rules are verified to permit internet access for server's subnet.
• NAT configuration is checked for correct routing of internet-bound traffic.
• Firewall logs are checked for any blocked traffic.
• Connectivity is checked with ping and traceroute to diagnose connection failures.

User Account Locked

• Checking password expiry in domain environments
• Resetting the user’s password if locked out
• Reviewing logs for login attempts.
• Checking network connection if domain authentication is required.
• Checking and clearing cached credentials

Failed Open Ports/Services Audit

• Identified open ports are reviewed in the firewall configuration.
• Validation if ports are essential to applications/services.
• Ports that are not necessary are closed.
• Logging for open ports is enabled.
• Routine port scans are scheduled for future unexpected open ports

Microsoft 365 issues

• OneDrive Sync Issues: Checking user login, disk space, cache clearing and checking the correctness of user account names/passwords.
• OneDrive Permissions Issues: Validating sharing permissions, email addresses, file restrictions and re-sharing files with correct permissions.
• SharePoint Access Denied: Verifying user permissions, validating account activity, clearing cache and checking for compliance policies.
• SharePoint Synchronization Issues: Confirming OneDrive installation, checking SharePoint permissions and clearing cached data.
• Email delivery failure: Checking for email policy restrictions, ensuring the email address is valid, testing with other external domains and checking if external domains are blocked.
• Email Attachment Issues: Checking file size limits, file sharing via other means such as links and confirming that the email client is updated.

Device Management

• Device enrollment failure: Checking user licenses, network connectivity, enrollment status page, enrollment restrictions and compliance policies.
• Autopilot Enrollment Issues: Verifying profile assignment, resetting device, checking internet connectivity, checking logs for errors
• Device non-compliance: Checking antivirus, compliance policy settings, syncing the devices and checking firewall settings
• Application Deployment Failures: Confirming App assignment and checking installation requirements.
• Security compliance policy warnings: Confirming compliance policy requirements and manually triggering a compliance check.
• Autopilot stuck in Identifying phase: Checking Network Access, reviewing Autopilot profile and resetting the device if needed..

Additional Notes

• Best practices and troubleshooting tips for ongoing management are discussed.
• Information is provided on resolving synchronization issues related to specific Microsoft 365 services (OneDrive and SharePoint), network connectivity, and device management.
• Best practices for resolving common email issues, like large file attachments, external domain problems, and bounce-back issues, are noted.
• Using tools like gpupdate /force, sfc /scannow, chkdsk /f, ipconfig /flushdns, netsh int ip reset, arp -a, tcping and others may help with troubleshooting different errors.

Test your knowledge on network troubleshooting techniques, including connectivity issues, VPN connectivity, and network latency problems. This quiz covers various methods and tools such as ping tests, firewall checks, and DNS resolution to diagnose and resolve network problems.