If you have multiple VPCs that connect to multiple on-premises locations, it’s recommended that you utilize a hub-and-spoke model, which helps get around reverse routing challenges due to the usage of the Google DNS proxy range. For redundancy, consider a model where the DNS-forwarding VPC network spans multiple Google Cloud regions, and where each region has a separate path (via interconnect or other means) to the on-premises network. This model allows the VPC to egress queries out of either interconnect path, and allows return queries to return via either interconnect path. The outbound request path always leaves Google Cloud via the nearest interconnect location to where the request originated.