We cannot connect back the ESXi host to the vCenter serve after changing the management IP of the ESXi host.

Products

• VMware vCenter Server 6.0
• VMware vCenter Server 7.0
• VMware vCenter Server 8.0

Issue/Introduction

ESXi state shows as  "not connected" on vCenter server , When we are trying to add the ESXi host to the vCenter server it says cannot reach the ESXi network.

Environment

vCenter server 6.x.x

vCenter server 7.x.x

vCenter server 8.x.x

Cause

vCenter server is unable to resolve the FQDN of the ESXi host for its new IP, due to  stale DNS entry.

Resolution

- We can ping the ESXi host

- From local machine ESXi hostname can resolve to the correct IP address. 

- We will have to clear the old entries of the this ESXi from the vCenter server. 

-  Flush the DNS entries from the vCenter server for which restart the DNS service.

systemctl restart dnsmasq.service