NAT Instances and NAT Gateways

  • NAT Instance: Network Address Translation(NAT).Its basically a process of taking the private ip address and translating it to public ip address so it allows you to connect to the public internet.

    • It's managed by you
    • The only way to scale this is to do it manually which means using a powerful and bigger instance with more resources and enhanced networking with additional bandwith.
    • There's no high availability and it has to be done manually.
    • Need to assign security groups.
    • Can be used as bastion host.
    • You can use an Elastic IP address or a public address with a NAT instance.
    • Can implement port forwarding manually

  • NAT Gateway: A better version of NAT Instance.

    • Its managed by AWS
    • Its elastically scaled upto 45 GBps
    • Provides automatic high availability within an AZ and can be placed in multiple AZs.
    • No security groups
    • Cannot be accessed through ssh
    • Choose the Elastic IP address to associate with a NAT instance gateway at creation.
    • Doesn't support port forwarding.

  • Lastly Private Subnet contains nat-gateway-id instead of igw-id and anything that isn't defined within ip cidr block of private subnet route table is handled by the nat-gateway-id.