A VMM endpoint off of a UCSB is unable to hit its anycast gateway, but the MAC address of the VM can be seen in one of the fabric interconnects. Wh1Ch option is the cause of the issue?

Question

Options

• AThe active NIC on the host has gone down and the host has not yet failed over.
• BThere is no native VLAN configured within the data path of the vCisco UCS.
• CLLDP is not enabled in the vSwitch policies.
• DThe VLAN tag is being changed at the vNIC or uplink port.

• A
  9% (4)
• B
  13% (6)
• C
  4% (2)
• D
  73% (33)

Explanation

Option D is correct because the MAC address being visible in the fabric interconnect confirms Layer 2 connectivity exists, meaning frames are arriving at the fabric - but with the wrong VLAN tag. In a Cisco UCS + ACI environment, the anycast gateway is tied to a specific bridge domain and VLAN; if the VLAN tag is altered at the vNIC template or uplink port policy, traffic arrives on the wrong VLAN and the fabric cannot map it to the correct EPG, so the gateway is unreachable. Option A is eliminated because a failed NIC with no failover would mean the MAC wouldn't be seen in the fabric interconnect at all. Option B (missing native VLAN) would affect untagged traffic paths and not produce this specific symptom pattern, since VM traffic in UCS/ACI is typically tagged. Option C (LLDP disabled) affects topology discovery and VMM integration visibility, not data plane forwarding to the gateway.

Memory tip: "MAC seen but gateway missed = VLAN mislabeled." If the endpoint is visible but unreachable, the frame is arriving on the wrong VLAN - point your investigation at where tags can be changed (vNIC or uplink policies in UCS).

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