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Before deploying a new VMware Cloud Foundation (VCF) 9.0 environment, the VCF Installer performs a number of validations including network MTU. The minimum MTU that is required to deploy VCF is 1600, which is used for the Tunnel Endpoint (TEP) for NSX traffic between your ESX hosts.

For most environments, this is not an issue and users will typically deploy VCF with Jumbo Frames enabled and configure the MTU with value of 9000. If your environment does not meet the minimum MTU requirement, the VCF Installer will flag this as an error and prevent you from deploying as shown in the screenshot below.

If you can not meet the MTU requirement, you can bypass the validation check so that you can continue with your deployment of the VCF Management Domain.

Step 1 - SSH to the VCF Installer using the vcf user and then run the following two commands:

sudo echo "validation.disable.network.connectivity.check=true" >> /etc/vmware/vcf/domainmanager/application.properties
sudo echo "nsxt.mtu.validation.skip=true" >> /etc/vmware/vcf/domainmanager/application.properties

Step 2 - Restart the VCF Installer services for the changes to go into effect by running the following command:

echo 'y' | /opt/vmware/vcf/operationsmanager/scripts/cli/sddcmanager_restart_services.sh

Once the VCF Installer services has successfully restarted, you can re-run the validation and it should now allow you to proceed with the deployment.