Understand the difference between NAT Gateways and public IPs in Vultr.
A NAT Gateway and a Public IP both enable internet connectivity for instances, but they solve fundamentally different networking problems. The core distinction is how traffic enters and leaves your network:
A NAT (Network Address Translation) Gateway provides shared, outbound-only internet access for instances that use private IP addresses.
Traffic initiated by an instance is translated at the gateway using source NAT (SNAT), replacing the private source IP with a public IP owned by the gateway. The gateway tracks connection state so that only response traffic for established outbound connections is allowed back in. Any unsolicited inbound traffic is dropped.
A Public IP is a globally routable address assigned directly to an instance or its network interface, enabling direct inbound and outbound connectivity.
The instance can send traffic to the internet without translation and can also receive inbound traffic addressed to its public IP. Inbound access is controlled using firewall rules or security groups, but the instance is fundamentally internet-facing.
In short, use a NAT Gateway for secure, outbound-only internet access from private workloads, and use a Public IP when an instance must be directly reachable from the internet.