Vpc

Overview Both connect a VPC to the internet, but they serve opposite purposes: an Internet Gateway lets public-facing resources send and receive traffic directly, while a NAT Gateway lets private resources reach out without ever being reachable from outside. Picking the wrong one either exposes resources you meant to keep private or silently blocks the outbound access your servers need. Comparison Diagram Internet GatewayNAT GatewayInternetInternetno inboundIGWNAT GatewayPublic SubnetInstancehas public IPPrivate SubnetInstanceprivate IP onlybidirectional trafficoutbound only Comparison Table Aspect Internet Gateway NAT Gateway Primary purpose Enables communication between a VPC and the internet in both directions Enables outbound-only internet access for resources without public IPs Traffic direction Bidirectional — accepts inbound connections and sends outbound Outbound only — inbound traffic allowed only as replies to established connections Placement Attaches directly to the VPC as a whole Deployed inside a specific public subnet IP address handling 1:1 NAT between a private IP and an Elastic/public IP Many-to-one PAT — many private IPs share the gateway’s public IP Which resources use it Instances with a public/Elastic IP routed via a public subnet route table Instances with only private IPs routed via a private subnet route table Scaling and availability Managed, horizontally scaled, highly available with no bandwidth cap Bandwidth-bounded per gateway; needs one per AZ for high availability Cost model No hourly charge and no data processing fee Hourly charge plus per-GB data processing fee Failure impact Loss cuts off all direct internet reachability for the public subnet Loss cuts off outbound internet access for the private subnet only Key Differences Internet Gateway provides bidirectional access; NAT Gateway only permits outbound connections. Internet Gateway attaches to the whole VPC; NAT Gateway lives inside a specific subnet. Internet Gateway does 1:1 Elastic IP mapping; NAT Gateway does many-to-one PAT. NAT Gateway bills per GB processed; Internet Gateway is free. When to Use Each Internet Gateway ...