You are planning to use Z-Tunnel 2.

Comprehensive and Detailed 100 to 150 words of Explanation From Zscaler Digital Transformation Administrator topics:

Z-Tunnel 2.0 normally uses Datagram Transport Layer Security (DTLS) because its UDP-based transport supports efficient forwarding of TCP, UDP, and ICMP traffic with lower transport overhead. When UDP connectivity is unavailable, blocked, or unstable, Zscaler Client Connector can fall back to TLS over TCP to preserve secure connectivity to the Zscaler service. The fallback is therefore from DTLS to TLS, not the reverse. IPsec is not the fallback transport used by Client Connector for this Z-Tunnel 2.0 behavior. Zscaler’s official documentation states that Z-Tunnel 2.0 uses DTLS or TLS, and its administrator study guide clarifies that DTLS is preferred for performance with TLS used when UDP is blocked. This makes B the precise answer.

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