title: AWS TransitGateway VPN Routes Remain in Blackhole State
body: <p>Has someone here succeeded in implementing an AWS VPN Connection with AWS TransitGateway service?</p>
  
  <p>I've created and configured my transit gateway and attachement of type VPN, with a transit gateway route table and association.
  I've downloaded the resulting vpn connection with static routing configuration and configured my on-prem routers, and my tunnels are up.</p>
  
  <p>However :</p>
  
  <ul>
  <li>I can reach my tunnels' public IP addresses from the on-prem network
  and AWS VPC</li>
  <li>I can reach my tunnels' public IP addresses from my on-prem
  network</li>
  <li>I can't reach my on-prem router's public IP address</li>
  <li>I can't reach any host from my on-prem network to AWS VPC, and inversely </li>
  </ul>
  
  <p>When I look at the corresponding transit gateway route table, I can see all VPN routes are in <code>blackhole</code> state. If I set them to the active state, but they still come back to <code>blackhole</code> state. In this <code>blackhole</code> state the TransitGateway drops packets silently...</p>
  
  <p>Any help?</p>