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PROFESSIONAL-CLOUD-NETWORK-ENGINEER · Question #54

Your company just completed the acquisition of Altostrat (a current GCP customer). Each company has a separate organization in GCP and has implemented a custom DNS solution. Each organization will…

The correct answer is B. Set up some variant of DNS forwarding and zone transfers in each organization. C. Connect VPCs in both organizations using Cloud VPN together with Cloud Router. Two things are needed to enable full cross-organization connectivity while retaining separate domains and hostnames: (1) Network connectivity: Cloud VPN with Cloud Router establishes encrypted tunnels between VPCs across organizations with dynamic routing via BGP, which is…

Submitted by carter_n· Apr 18, 2026Implementing a Google Cloud network

Question

Your company just completed the acquisition of Altostrat (a current GCP customer). Each company has a separate organization in GCP and has implemented a custom DNS solution. Each organization will retain its current domain and host names until after a full transition and architectural review is done in one year. These are the assumptions for both GCP environments. - Each organization has enabled full connectivity between all of its projects by using Shared VPC. - Both organizations strictly use the 10.0.0.0/8 address space for their instances, except for bastion hosts (for accessing the instances) and load balancers for serving web traffic. - There are no prefix overlaps between the two organizations. - Both organizations already have firewall rules that allow all inbound and outbound traffic from the 10.0.0.0/8 address space. - Neither organization has Interconnects to their on-premises environment. You want to integrate networking and DNS infrastructure of both organizations as quickly as possible and with minimal downtime. Which two steps should you take? (Choose two.)

Options

  • AProvision Cloud Interconnect to connect both organizations together.
  • BSet up some variant of DNS forwarding and zone transfers in each organization.
  • CConnect VPCs in both organizations using Cloud VPN together with Cloud Router.
  • DUse Cloud DNS to create A records of all VMs and resources across all projects in both
  • ECreate a third organization with a new host project, and attach all projects from your company

How the community answered

(32 responses)
  • A
    13% (4)
  • B
    56% (18)
  • D
    9% (3)
  • E
    22% (7)

Explanation

Two things are needed to enable full cross-organization connectivity while retaining separate domains and hostnames: (1) Network connectivity: Cloud VPN with Cloud Router establishes encrypted tunnels between VPCs across organizations with dynamic routing via BGP, which is important since both orgs use Shared VPC and have non-overlapping 10.0.0.0/8 address space. (2) DNS resolution: DNS forwarding and zone transfers allow each organization's instances to resolve hostnames in the other organization's domain, which is critical since both orgs retain their own domains. Option A (Cloud Interconnect) is for on-premises-to-GCP connectivity, not GCP-to-GCP. Option D (manual A records in Cloud DNS) is operationally expensive and error-prone at scale. Option E (third organization) is unnecessarily complex.

Topics

#Multi-organization networking#Cloud VPN#Cloud Router#Cloud DNS forwarding

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