> ## Documentation Index > Fetch the complete documentation index at: /docs/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > Agent home for Datum, with what it is, pricing, and how to act: https://agents.datum.net > If you can only fetch URLs: read https://www.datum.net/docs/llms.txt in full and open the most specific page for the task. Commands, limits, and field paths are on task, operations, and limits pages, not on section overviews. Pages described as "Documentation is coming soon" are placeholders. > If you have a shell or can save files: download https://www.datum.net/docs/llms-full.txt (every page, about 740 KB) once and search it with grep, instead of fetching pages one at a time. > datumctl describes itself: `datumctl api-resources` lists resource types and `datumctl explain ` shows a schema. To act on live resources, use Datum MCP or datumctl. To search the docs, use the Docs MCP server at https://www.datum.net/docs/mcp. # Traffic and connecting > Learn which traffic a gVPC network carries and how Instances connect to each other. A network carries private traffic between Instances. This page describes which kinds of traffic are possible and how Instances connect to each other. To learn how Instances get their addresses, see [Addressing](/docs/galactic-vpc/networks/addressing.md). > [!NOTE] > > [gVPC](/docs/galactic-vpc/overview.md) is in preview, and the `networking.datumapis.com/v1alpha` API can change. ## What traffic a network carries The following table describes which kinds of traffic are possible: | Traffic | Available | Details | | - | - | - | | Between Instances on the same network in the same location | Yes | Instances use their private IPv6 addresses. Any Instance can connect to any port on another Instance in the same network and location. | | Between Instances on the same network in different locations | Yes | A network spans locations, and Instances can connect to each other privately across locations using their private IPv6 addresses. | | Between different networks | No | Networks are isolated from each other. | | To or from other addresses through an Instance | No | A network only delivers a packet addressed to an Instance's own address, and only accepts a packet from an Instance's own address. An Instance can't route traffic for other addresses, so a router or VPN appliance needs an overlay, such as VXLAN or a UDP tunnel, between Instances. | | Inbound from the internet | Through Datum's ALB | Instance addresses aren't reachable from the internet directly. Public HTTP and HTTPS traffic reaches Instances through Datum's [Application Load Balancer](/docs/alb/overview.md). Raw TCP and UDP exposure is a preview limitation. | | Outbound to the internet | Yes | Instances can reach internet destinations, including services that have only IPv4 addresses. | | Lookups by name | Not in the preview | Private DNS names for Instances are on the [roadmap](/docs/galactic-vpc/limitations-and-roadmap.md#planned-capabilities). Use IPv6 addresses in the preview. | | Firewall filtering | Not in the preview | Firewall rules to filter traffic between Instances on a network are on the [roadmap](/docs/galactic-vpc/limitations-and-roadmap.md#planned-capabilities). | The workload API accepts a `networkPolicy` field on each network interface, but the field has no effect. Don't rely on it to restrict traffic. To limit who can reach a service, check credentials in your app, or put services that must stay apart on different networks. Firewall rules for networks are on the [roadmap](/docs/galactic-vpc/limitations-and-roadmap.md#planned-capabilities). ## Connect to other Instances To connect from one Instance to another on the same network, use the peer's private IPv6 address. Keep the following points in mind: * Make your app listen on IPv6 (`::`). An app that listens only on `0.0.0.0` accepts IPv4 connections only, and Instances don't have IPv4 addresses. * In a URL, put an IPv6 address in square brackets, such as `http://[fd20:4a3b:91c2:1::1:0:2]:8080/`. * Private DNS names aren't available in the preview. To tell an app about its peers, pass their addresses in environment variables or a ConfigMap. ## What's next * To serve a workload publicly through Datum's ALB, see [Compute and ALB](/docs/compute/compute-and-alb.md). * To review what networks can't do, see [Limitations and roadmap](/docs/galactic-vpc/limitations-and-roadmap.md). This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.