App-ID and HTTP/2 Inspection

Palo Alto Networks firewalls can inspect and enforce security policy for HTTP/2 traffic, on a stream-by-stream basis.
You can now safely enable applications running over HTTP/2, without any additional configuration on the firewall. As more websites continue to adopt HTTP/2, the firewall can enforce security policy and all threat detection and prevention capabilities on a stream-by-stream basis. This visibility into HTTP/2 traffic enables you to secure web servers that provide services over HTTP/2, and allow your users to benefit from the speed and resource efficiency gains that HTTP/2 provides.
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The firewall processes and inspects HTTP/2 traffic by default when SSL decryption is enabled. For HTTP/2 inspection to work correctly, the firewall must be enabled to use ECDHE (elliptic curve Diffie-Hellman) as a key exchange algorithm for SSL sessions. ECDHE is enabled by default, but you can check to confirm that it’s enabled by selecting ObjectsDecryptionDecryption ProfileSSL DecryptionSSL Protocol Settings.
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You can disable HTTP/2 inspection for targeted traffic, or globally:
  • Disable HTTP/2 inspection for targeted traffic.
    You’ll need to specify for the firewall to remove any value contained in the Application-Layer Protocol Negotiation (ALPN) TLS extension. ALPN is used to secure HTTP/2 connections—when there is no value specified for this TLS extension, the firewall either downgrades HTTP/2 traffic to HTTP/1.1 or classifies it as unknown TCP traffic.
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    1. Select ObjectsDecryptionDecryption ProfileSSL DecryptionSSL Forward Proxy and then select Strip ALPN.
    2. Attach the decryption profile to a decryption policy (PoliciesDecryption) to turn off HTTP/2 inspection for traffic that matches the policy.
    3. Commit your changes.
  • Disable HTTP/2 inspection globally.
    Use the CLI command: set deviceconfig setting http2 enable no and Commit your changes. The firewall will classify HTTP/2 traffic as unknown TCP traffic.

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