Unable to save DNS server changes in vCenter TCP/IP stack configuration for ESXi hosts

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

When attempting to add additional DNS servers to the TCP/IP Stack Configuration for an ESXi host within the vCenter inventory, the changes are not saved. After navigating to the host's Configure tab > TCP/IP Configuration, editing the default stack, and clicking "OK", vCenter rejects the modification and displays a red exclamation icon next to the DNS configuration.

When attempting the same configuration directly in the ESXi web UI (Networking > TCP/IP Stacks > Default TCP/IP stack > Edit settings), the following errors are displayed:

Please provide valid search domains
Please provide a valid domain name

Environment

VMware vCenter
VMware ESXi

Cause

This issue occurs because the Domain name and Search Domain fields are mandatory parameters for the TCP/IP stack. If these fields are left blank when updating the DNS settings, input validation fails and prevents the new configuration from saving.

Resolution

To resolve this issue, you must fully populate the DNS configuration fields:

1. Select the affected ESXi host in the vCenter inventory.
2. Navigate to the Configure tab and select TCP/IP Configuration.
3. Click "edit" on the default stack.
4. Ensure you input valid values for all the following fields:
   
   
   • Hostname
   • Domain name
   • Primary DNS server
   • Secondary DNS server (optional)
   • Search domain
     
     
5. Click OK. vCenter will now accept and save the configuration update.

Additional Information

For additional reference: How to change ESXi host DNS server IP