Which statement about the default MAC address for the distributed gateway in the Cisco ACI Fabric is true?

Question

Options

• AThere is no default MAC address.
• BA custom MAC address must be configured under each bridge domain.
• CThe default MAC address is 00:11:BD:F8:88:0C.
• DThe default MAC address is 00:22:BD:F8:19:FF.

• B
  91% (32)
• C
  3% (1)
• D
  6% (2)

Explanation

In Cisco ACI, the distributed (anycast) gateway is configured at the Bridge Domain (BD) level, and a MAC address must be explicitly defined under each BD rather than being inherited from a global default. Without this per-BD configuration, the gateway cannot function correctly, making B correct - the onus is on the administrator to assign the MAC address during BD setup.

Why the distractors are wrong:

• A is incorrect because a MAC address is required - it simply must be manually configured rather than being a pre-existing default.
• C (00:11:BD:F8:88:0C) is a fabricated value with no basis in ACI documentation and is a classic distractor using a plausible-looking MAC.
• D (00:22:BD:F8:19:FF) is a well-known red herring that appears in ACI discussions (often as an example or misremembered value), but it does not represent a fabric-wide default that auto-populates each BD.

Memory tip: Think of it this way - ACI's distributed gateway is distributed, meaning each Bridge Domain is independent and owns its own identity (MAC). Nothing is assumed for you; every BD must be explicitly told "this is your MAC." If it were truly a global default, it wouldn't be distributed - it would be centralized.

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