Networking

Networking on Fly.io.

• Connect to an App Service: An overview of how to connect to your app over the private WireGuard network (6PN), and how to make your app reachable from the internet.

• Private networking: Learn about Fly.io’s IPv6 private network (6PN), DNS on Fly Machines, and how to use Flycast for load balancing and other Fly Proxy features on a private network.

• Public networking: Details about public network services on Fly.io, including allocating IP addresses, finding a Machine’s outbound IP, connection handlers, and redirects.

• Dynamic request routing: Use the fly-replay response header to route requests to other apps and regions.

• Custom domains: Add a custom domain for your app and troubleshoot certificate creation.

• Automate the certificate process with the GraphQL API: If you need to issue multiple certificates automatically for custom domains, you can do that with the GraphQL API.

• HTTP request headers: Fly.io-specific and standard HTTP headers added by the HTTP connection handler.

• Run UDP services: How to set up apps that use UDP.

• TLS support: Supported TLS cipher suites.

Related topics

• Fly Proxy
• How Fly Proxy does load balancing
• Fly Regions