After the Kaspersky Endpoint Security for Windows update, the computer does not work properly on the Internet

[James Johnson]

After upgrading Kaspersky Endpoint Security for Windows from 12.6 to 12.7.0.533, the computer cannot access the internet properly. Only applications that were accessing the network when Kaspersky Endpoint Security for Windows was launched can go online after the application starts. Any applications that attempt to connect to the internet after Kaspersky Endpoint Security for Windows has started encounter the err_connection_reset error. For example, when Kaspersky Endpoint Security for Windows starts with the system, only the system (Windows updates can update normally) and Kaspersky Endpoint Security for Windows can connect to the internet. At this point, if Kaspersky Endpoint Security for Windows is exited, all applications can connect to the internet normally. If Chrome is opened and used, then when Kaspersky Endpoint Security for Windows is restarted, Chrome can still access the internet and browse web pages. However, if Edge is opened at this time, it will prompt that the connection has been reset, showing err_connection_reset, and other applications will also be unable to connect to the internet. I checked the reports from Kaspersky Endpoint Security for Windows, and no related events were recorded. I tried uninstalling and reinstalling Kaspersky Endpoint Security for Windows, but the problem was not resolved.

[KarDip]

Hello @James Johnson

The issue you are experiencing with Kaspersky Endpoint Security for Windows (KES) version 12.7.0.533 could be related to several possible causes, including a misconfiguration in the Network Threat Protection component, Firewall settings, or conflicts with other software. Here is a structured approach to troubleshoot and resolve the issue:

 Here is a structured approach to troubleshoot and resolve the issue:

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1. Check Network Threat Protection (NTP) Settings

1. Open the KES interface on the affected computer.
2. Navigate to Settings > Protection Components > Network Threat Protection.
3. Temporarily disable Network Threat Protection to check if the issue persists.
   • If disabling this resolves the issue, inspect and fine-tune the NTP settings or add exclusions for specific applications or traffic.
   • You may need to adjust the "Protocol Inspection" settings.

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2. Verify Firewall Configuration

1. Open KES > Settings > Firewall.
2. Check the active Firewall rules and ensure:
   • There are no blocking rules affecting applications that cannot connect.
   • The general rule for Allow outbound traffic is active and properly configured.
3. If there are custom rules, temporarily disable them and test the connectivity.

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3. Adjust Application Control Settings

1. Go to Settings > Protection Components > Application Control.
2. Check whether the affected applications (e.g., Edge) are restricted or assigned to an inappropriate category.
3. Assign them to a trusted category and test again.

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4. Review Trusted Zone Configuration

1. Check if the affected applications are listed under Settings > Threats and Exclusions > Specify Trusted Applications.
2. Add the affected browsers and other impacted applications to the trusted zone.

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5. Disable Self-Defense Temporarily

1. Go to Settings > General.
2. Temporarily disable the Self-Defense feature.
3. Restart the application and test network access. If this resolves the issue, re-enable Self-Defense after testing and escalate to Kaspersky support.

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6. Review Diagnostic Logs

1. Navigate to the KES Console > Reports and Quarantine.
2. Generate a diagnostic log after reproducing the issue:
   • Look for any hints in the logs related to blocked traffic or restricted applications.

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7. Update or Repair the Network Agent

If you are managing devices via Kaspersky Security Center (KSC):

1. Verify that the Network Agent is updated to match the KES version.
2. Reinstall the Network Agent and ensure proper communication with the KSC.

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8. Check for Conflicting Software

1. Ensure no other security software or VPN is interfering with the network stack.
2. If present, temporarily disable or uninstall third-party software for testing.

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9. Use Network Trace Tools

Use diagnostic tools like Wireshark or Microsoft Message Analyzer to:

1. Monitor traffic when KES is active versus when it is not.
2. Identify where the connection is reset or blocked.

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10. Update to the Latest Patch

Ensure KES 12.7.0.533 has the latest updates applied:

1. Open KES > Update and force a manual update.
2. Apply any available hotfixes or patches from the Kaspersky Business Support Portal.

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11. Escalate to Kaspersky Support

If the above steps do not resolve the issue:

1. Collect the necessary logs:
   • System logs.
   • KES logs from the affected machine.
   • Network Agent logs (if managed through KSC).
2. Contact Kaspersky Business Support with detailed information and diagnostic logs.

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Let me know if you need guidance on specific steps, such as enabling logging or capturing network traces.

Thank you