title: Create 3 VNETS where all traffic is routed through one VNET (hub and spoke)
body: <p>I'm trying to figure out how to answer I question I recently had on an exam.  The requirements are as follows:</p>
  
  <ol>
  <li>You plan on creating 100 VMs across 3 virtual networks (vnetA, vnetB, and vnetC)</li>
  <li>All traffic must be routed through vnetA</li>
  <li>All virtual machines must be able to talk to each other via private IP</li>
  <li>Solution must not require any virtual gateways</li>
  <li>Solution must minimize the number of peerings.</li>
  <li>Solution must not require any network virtual appliance (VM acting as router)</li>
  </ol>
  
  <p>To me, this sounds like a hub and spoke topology where I perform the following steps.</p>
  
  <ol>
  <li>Create vnet peering from vnetA to vnetB (allow forwarded traffic)</li>
  <li>Create vnet peering from vnetB to vnetA</li>
  <li>Create vnet peering from vnetA to vnetC (allow forwarded traffic)</li>
  <li>Create vnet peering from vnetC to vnetA</li>
  </ol>
  
  <p>Now I need the spoke to spoke connectivity (between vnetB and vnetC) but it has to pass through vnetA which is where I get confused.  My first thought was to simply enable Allow gateway transit/Use remote gateways options between the two peerings above, but it doesn't allow that due to vnetA not having  virtual network gateway (I even tried adding a GatewaySubnet to vnetA).</p>
  
  <p>I can't seem to use a custom route table attached to the subnets of vnetB and vnetC to specify a next hop unless I use a virtual appliance which can't be used in this solution.  </p>
  
  <p>Anyone have any ideas on how they would approach this problem?</p>