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Networking

Networking decides who can reach your instances and what they can reach. Everything here lives in the project's location: a network in Karachi never reaches one in Islamabad by itself.

How traffic reaches your instances and the Internet In one location, the project's private routing joins its networks. An Internet gateway lets instances reach the Internet through a shared outbound address. A public IP brings traffic from the Internet to one instance, here web-1 on the network app. web-2 has no public IP: it can reach out through the gateway but cannot be reached from the Internet. Internet Internet gateway outbound via 198.51.100.2 Public IP 203.0.113.21 → web-1 Private routing joins your networks Network · app 10.0.0.0/24 web-1 10.0.0.11 web-2 10.0.0.12 out in
In one location: private routing joins the project's networks, the Internet gateway takes traffic out, and a public IP brings traffic in to one instance.

  • Networks

    Private address ranges for your instances, with DHCP, DNS and static ranges.

  • Routing

    The project's private router, routes through an instance, and forwarding.

  • Internet gateways

    Outbound Internet access for routed networks, through one shared address.

  • Security groups

    Firewall rules: which traffic may reach an instance, and what it may send.

  • Public IPs

    Addresses that make one instance or load balancer reachable from the Internet.

  • Load balancers

    One address for several instances, with health checks and HTTPS.

  • Network topology

    A drawing of a project's networks and what is connected to each.

The path of a packet

You want You need
Instances to talk to each other The same network, or two routed networks of the project, and security group rules that allow it
Instances to reach the Internet A routed network and an Internet gateway in the project
The Internet to reach an instance All of the above, a public IP on the instance, and a rule that allows the port
One address for several instances A load balancer with a public IP, and rules that let it reach the instances
Traffic to an office or VPN range A route through an instance that forwards for that range

A new project made with Set up a network and Create an Internet gateway has a routed network, default (10.0.0.0/24), and a gateway from the start.