Notes and Constraints¶
Public NAT Gateway¶
When using a public NAT gateway:
Multiple rules for one public NAT gateway can use the same EIP, but the rules for different NAT gateways must use different EIPs.
Each VPC can only have one NAT gateway.
Only one SNAT rule can be added for each VPC subnet.
SNAT and DNAT rules cannot use the same EIP.
DNAT rules cannot map virtual IP addresses to EIPs.
If both an EIP and a public NAT gateway are configured for a server, data will be forwarded through the EIP.
If the rule is used in the Direct Connect scenario, the custom CIDR block must be a CIDR block of a Direct Connect connection and cannot overlap with the NAT gateway's VPC subnets.
Only one DNAT rule can be configured for each port on a server. One port can be mapped to only one EIP.
Up to 200 DNAT rules can be added to a public NAT gateway. The number of SNAT rules that can be added to a public NAT gateway is not limited.