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NTLM authentication fails with "401 Unauthorized" when the proxy feature is enabled on Security Gateway Technical Level
  • When trying to connect to a site that requires NTLM authentication from Internet Explorer browser, the authentication pop-up does not appear, and the message "401 Unauthorized" immediately appears instead.

  • When using Chrome browser or Firefox browser, the authentication pop-up appears. However, valid credentials will also redirect to "401 Unauthorized" message.


Proxy feature does not support NTLM authentication.


This feature is not included in the product. If you need it, please submit a Request for Enhancement.

NTLM authentication for proxy server is also not supported for manual IPS updates.

This solution has been verified for the specific scenario, described by the combination of Product, Version and Symptoms. It may not work in other scenarios.

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