ESXi host disconnection from vCenter

Products

• VMware vSphere ESXi
• VMware vCenter Server

Issue/Introduction

• ESXi host gets into a disconnected state from vCenter.
• Below logs are observed in vpxd logs of vCenter:
  
  2026-07-31T12:02:37.177Z warning vpxd[06472] [Originator@6876 sub=InvtHostCnx opID=HB-host-####@58602-#####] Exception occurred during host sync; Host communication failed; [vim.HostSystem:host-####,esx-##.example.local], e: N5Vmomi5Fault17HostCommunication9ExceptionE(Fault cause: vmodl.fault.HostCommunication
  
  
• DNS Resolution failure logs are observed in dnsmasq logs on vCenter for the concerned host:
  
  Jul 31 12:01:22 dnsmasq[2177]: forwarded esx-##.example.local to <upstream-DNS-server>
Jul 31 12:01:22 dnsmasq[2177]: forwarded esx-##.example.local to <upstream-DNS-server>
Jul 31 12:01:22 dnsmasq[2177]: reply esx-##.example.local is NXDOMAIN
Jul 31 12:01:22 dnsmasq[2177]: query[A] esx-##.example.local from 127.0.0.1
Jul 31 12:01:22 dnsmasq[2177]: cached esx-##.example.local is NXDOMAIN
  
  
  

Environment

VMware vCenter Server

VMware vSphere ESXi

Cause

The DNS resolution failure for the host on vCenter results in host disconnection from VC.

Resolution

This will require a network-level investigation to trace and verify connectivity along with packet exchange between the vCenter server and the DNS server.