Azure Front Door
An Azure service that provides a cloud content delivery network with threat protection.
Issue with Azure Front Door WAF JA4 condition
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May Xu
0
Reputation points
Based on Q&A document, looks like we need Microsoft to enable JA4 feature for my subscription. This support request is asking microsoft to enable it for my subscription - subscription 1.
please contact me if you need any further information through my email
Azure Front Door
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May Xu 0 Reputation points
2026-06-01T17:46:27.7433333+00:00 Please enable/confirm the JA4 / ClientFingerprint feature flag for Azure Front Door WAF on this subscription and region.
Removed PII
We can deploy a rule using matchVariable=JA4 and operator=ClientFingerprint, and access logs show clientJA4FingerPrint_s is populated. However, requests with matching JA4 do not trigger the custom rule. When we remove only the JA4 condition, the same request triggers CAPTCHA correctly. Please enable or validate backend runtime support for JA4 ClientFingerprint matching.
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Ravi Varma Mudduluru 12,625 Reputation points Microsoft External Staff Moderator2026-06-05T06:03:30.8466667+00:00 Hello @May Xu
Thank you for reaching out to Microsoft Q&A.
Could you please check the private message and share the requested details there?
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