A MAC address is a unique character string, and since it identifies a specific physical device — one individual NIC — the MAC address, by convention, never changes for the life of the NIC.

一个MAC地址是一个独一无二的字符串。由于它标识一个独特的物理设备——一个唯一的网卡——MAC地址，按照约定，在网卡中将永不会改变。

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So, instead of catching and emulating access to physical devices below the hypervisor, new processors provide DMA address translation and permissions checking for efficient device passthrough.

因此，新的处理器提供DMA地址转换和权限检查以实现有效的设备透传，而不是捕获并模拟对管理程序下的物理设备的访问。

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The never-changing MAC provides a specific, reliable address for a physical device.

而永不变化的MAC地址给物理设备提供了一个独特可靠的地址。

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Security solutions based on physical infrastructure, and policy expressed in terms of a particular device, the corporate PC, an IP address, network port, or application protocol are becoming useless in a mobile, borderless world.

FORBES: Going Mobile: Security in the Age of Ubiquity