Which of the following is not a supported CHAP authentication method by ESXi?

ESXi supports several CHAP (Challenge-Handshake Authentication Protocol) authentication methods for securing communication between iSCSI initiators and targets. The method known as Triple CHAP is not among those supported by ESXi.

Initial CHAP, One-way CHAP, and CHAPv2 are all valid authentication methods used in various iSCSI implementations. Initial CHAP and One-way CHAP are used primarily for basic authentication, where only the initiator authenticates to the target. CHAPv2 enhances this by allowing mutual authentication, enabling both the initiator and target to prove their identities to each other.

In contrast, Triple CHAP does not have a defined standard or common usage in networking or iSCSI scenarios, making it unsupported in the ESXi environment. Therefore, understanding the supported authentication methods is crucial for configuring secure iSCSI communications in a vSphere environment.