title: Can you have two NAT gateways in a route table for one or more subnets?
body: <p>I have the following scenario:</p>
  
  <p>I have a <code>Public</code> and <code>Private</code> subnet in my VPC. The public subnet will send the traffic obviously through the internet gateway, and private goes through a separate NAT gateway.</p>
  
  <p>The issue I am faced with - is we have a Mail Server/Exchanger inside our private subnet. Right now, the NAT gateway that is serving our other EC2 devices has an elastic IP address. We need to provide a separate Elastic IP address to the MX server. Can that be done by setting up another NAT gateway? If so, how do I set up the route tables/subnets to handle that?</p>
  
  <p>I thought I may need to create a new subnet and place the MX in there, but am not entirely sure.</p>
  
  <p>The main reason for this all being the use of rDNS (Reverse DNS) - when email is sent from our MX server, it will have an origin IP address, which -should- map back to your sending TLD (@emailaddress.com) for spam circumvention.</p>
  
  <p>If I can get this MX server to route its outgoing traffic through the new NAT gateway, things will be great - because then I can just tell AWS to map the IP address provisioned to that rDNS arpa thing.</p>
  
  <p>What is the best course to follow here?</p>