---
title: "PUT /config/lfn"
method: PUT
path: "/config/lfn"
---

# PUT /config/lfn

`PUT /config/lfn`

Configure LFN specific settings. This method may only be issued to an LFN.

## Request body

- LfnConfig — LFN specific settings.
  - `routingMethod` integer, required — Set as specified in the [FANTPS] PAN-IE description.
  - `networkName` string, required — Set as specified in the [FANTPS] NETNAME-IE description.
  - `sixLowpanMtu` integer, required — The 6LoWPAN MTU to be used by this LFN.
  - `lgtkMaxMismatch` integer, required — Maximum time between a SUP detecting a LGTKHASH mismatch and the SUP initiating Msg1 of the authentication flow (causing the BR to initiate a Group Key handshake with the SUP).
  - `ndAddressRegistrationLifetime` integer — 16-bit unsigned integer. The lifetime, in minutes, of the LFN's GUA/ULA registration. [RFC 6775 Section 4.1]

## Response `200`

LFN successfully configured.

## Other responses

- `400` — Device is not an LFN.
- `default` — Unknown error occurred

## Changes

- **2025-01-07** `fa086964a1b1` — 1 info
  - endpoint added
- **2023-07-24** `11bc7842d64c` — 1 breaking
  - api path removed without deprecation

[Change history](https://skmtc.dev/siliconlabs/apis/tbu-api/changes/config/lfn/put.md)

---

[API](https://skmtc.dev/siliconlabs/apis/tbu-api.md) · [All operations](https://skmtc.dev/siliconlabs/apis/tbu-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/siliconlabs/tbu-api/revisions/8475de394ee2/schema)