2V0-621D · Question #127
After successfully adding a new ESXi 6.x host to vCenter Server, an administrator sees it as Not Responding in the vSphere Web Client interface a few minutes later. If the issue is caused by a…
The correct answer is D. 902 (UDP). When an ESXi host shows as 'Not Responding' in vCenter Server due to a firewall, the problem is specifically related to blocked UDP port 902, which is essential for vCenter to receive heartbeats from the ESXi host.
Question
After successfully adding a new ESXi 6.x host to vCenter Server, an administrator sees it as Not Responding in the vSphere Web Client interface a few minutes later. If the issue is caused by a network firewall blocking traffic, which port must be opened to correct this specific problem?
Options
- A443 (TCP)
- B443 (UDP)
- C902 (TCP)
- D902 (UDP)
How the community answered
(29 responses)- A3% (1)
- B3% (1)
- C10% (3)
- D83% (24)
Why each option
When an ESXi host shows as 'Not Responding' in vCenter Server due to a firewall, the problem is specifically related to blocked UDP port 902, which is essential for vCenter to receive heartbeats from the ESXi host.
TCP port 443 is used for vCenter Server to ESXi management communication and API calls, but the 'Not Responding' status is specifically linked to the heartbeat function, which primarily uses UDP 902.
UDP port 443 is not a standard port used for vCenter-ESXi communication or host heartbeats; secure web communication and API calls use TCP 443.
TCP port 902 is used for deploying VMs from templates and console access, but the 'Not Responding' status due to a missed heartbeat specifically points to the UDP 902 communication.
UDP port 902 is used by vCenter Server to receive heartbeats from ESXi hosts; if this port is blocked by a firewall, vCenter Server will lose contact and mark the ESXi host as 'Not Responding'.
Concept tested: vCenter-ESXi network port requirements (heartbeats)
Source: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.security.doc/GUID-D0C0820F-1D89-408E-927A-946E56306C9F.html
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