title: Amazon AWS NAT Gatway not working, EC2 doesn't register in ECS Cluster
body: <p>I'm convinced that my EC2 instance and cluster are configured correctly and that they won't register due to the network configuration.</p>
  
  <p>I am building EC2 instance from a auto-scaling group, they <em>will</em> register if I create/associate an Elastic IP to them however I cannot get them to NAT, as they will be auto-scaled I need them to use NAT to register themselves with the cluster.</p>
  
  <p>I have 1 VPC on network <code>10.0.0.0/0</code></p>
  
  <p>I have 3 subnets in 3 regions on ranges <code>10.0.0.0/24</code>, <code>10.0.1.0/24</code> &amp; <code>10.0.2.0/24</code>.</p>
  
  <p>I want to use Amazon's <code>NAT Gateway</code> not to be confused with <code>NAT Instance</code> which is an AMI to do this functionality.</p>
  
  <p>I have been following this guide @ <a href="http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-nat-gateway.html" rel="nofollow">http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-nat-gateway.html</a> </p>
  
  <p>(For now) I have a single route table (which all 3 subnets are assigned to) which is as follows...</p>
  
  <pre><code>10.0.0.0/16 | local
  0.0.0.0/0   | nat-******
  </code></pre>
  
  <p>The NAT Gateway sits on <code>10.0.2.19</code>.</p>
  
  <p>The security group is as follows</p>
  
  <pre><code>Inbound
  ALL TRAFFIC | ALL PROTOCOLS | ALL PORT RANGE |SOURCE: 0.0.0.0/0
  Outbound
  ALL TRAFFIC | ALL PROTOCOLS | ALL PORT RANGE |DESTINATION: 0.0.0.0/0
  </code></pre>
  
  <p>Network ACL is</p>
  
  <pre><code>Inbound
  Rule # | Type | Protocol | Port Range | Source | Allow / Deny
  100 | ALL Traffic | ALL | ALL | 0.0.0.0/0 | ALLOW
  * | ALL Traffic | ALL | ALL | 0.0.0.0/0 | DENY
  Outbound
  Rule # | Type | Protocol | Port Range | Destination | Allow / Deny
  100 | ALL Traffic | ALL | ALL | 0.0.0.0/0 | ALLOW
  * | ALL Traffic | ALL | ALL | 0.0.0.0/0 | DENY
  </code></pre>
  
  <p>Which suggests everything is allowed?</p>
  
  <p>I have attached a IP to one instance then connected over the VPC to another instance and try to ping the NAT gateway which is unsuccessful but I don't understand why? Everything here is set quite simply and it doesn't quite make sense?</p>
  
  <p>Help much appreciated :)</p>