> ## Documentation Index
> Fetch the complete documentation index at: https://developers.telnyx.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Routes

> Which subnets of a Network a Tailscale Subnet Router advertises to the tailnet.

The router advertises subnets of the [*Network*](/docs/network/overview) to the tailnet as [subnet routes](https://tailscale.com/docs/features/subnet-routers). After the subnet routes are approved, devices behind the router reach those subnets.

These ranges are reserved by Telnyx and cannot be advertised. The API rejects a route that overlaps any of them:

* `0.0.0.0/8`, and with it the default route
* `127.0.0.0/8`, loopback
* `169.254.0.0/16`, link-local
* `224.0.0.0/3`, multicast and reserved
* `100.64.0.0/10`, Tailscale's own addresses
* `172.27.254.0/24` and `198.18.0.0/20`, the router's own addresses

A `PATCH` with a new `advertised_routes` list replaces the advertisement. The router keeps its machine on the tailnet.

## For the Tailnet Admin

* Approve each route in the admin console, or let [`autoApprovers`](https://tailscale.com/docs/reference/syntax/policy-file#autoapprovers) approve it.
* Grant access to the routes with an [access rule](https://tailscale.com/docs/features/subnet-routers#add-access-rules-for-the-advertised-subnet-routes). Approval puts a route on devices. Access rules decide which traffic passes. The [route injection reference](https://tailscale.com/docs/reference/route-injection) covers both.
* Android, iOS, macOS, tvOS, and Windows devices [pick up the routes](https://tailscale.com/docs/features/subnet-routers#use-your-subnet-routes-from-other-devices) automatically. Linux devices need `tailscale set --accept-routes`.