---
labels:
- 'Stage-Alpha'
- 'Type-S2SAuth'
summary: S2S authentication using DANE
...

Introduction
============

This module implements DANE as described in [Using DNS Security
Extensions (DNSSEC) and DNS-based Authentication of Named Entities
(DANE) as a Prooftype for XMPP Domain Name
Associations](http://tools.ietf.org/html/draft-miller-xmpp-dnssec-prooftype).

Dependencies
============

This module requires a DNSSEC aware DNS resolver. Prosodys internal DNS
module does not support DNSSEC. Therefore, to use this module, a
replacement is needed, such as [this
one](https://www.zash.se/luaunbound.html).

LuaSec 0.5 or later is also required.

Configuration
=============

After [installing the module][doc:installing\_modules], just add it to
`modules_enabled`;

    modules_enabled = {
     ...
     "s2s_auth_dane";
    }

DANE Uses
---------

By default, only DANE uses are enabled.

    dane_uses = { "DANE-EE", "DANE-TA" }

  Use flag    Description
  ----------- -------------------------------------------------------------------------------------------------------
  `DANE-EE`   Most simple use, usually a fingerprint of the full certificate or public key used the service
  `DANE-TA`   Fingerprint of a certificate or public key that has been used to issue the service certificate
  `PKIX-EE`   Like `DANE-EE` but the certificate must also pass normal PKIX trust checks (ie standard certificates)
  `PKIX-TA`   Like `DANE-TA` but must also pass normal PKIX trust checks (ie standard certificates)

DNS Setup
=========

In order for other services to verify your site using using this plugin,
you need to publish TLSA records (and they need to have this plugin).
Here's an example using `DANE-EE Cert SHA2-256` for a host named
`xmpp.example.com` serving the domain `example.com`.

    $ORIGIN example.com.
    ; Your standard SRV record
    _xmpp-server._tcp.example.com IN SRV 0 0 5269 xmpp.example.com.
    ; IPv4 and IPv6 addresses
    xmpp.example.com. IN A 192.0.2.68
    xmpp.example.com. IN AAAA 2001:0db8:0000:0000:4441:4e45:544c:5341

    ; The DANE TLSA records.
    _5269._tcp.xmpp.example.com. 300 IN TLSA 3 0 1 E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855

    ; If your zone file tooling does not support TLSA records, you can try the raw binary format:
    _5269._tcp.xmpp.example.com. 300 IN TYPE52 \# 35 030001E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855

[List of DNSSEC and DANE
tools](http://www.internetsociety.org/deploy360/dnssec/tools/)

Further reading
===============

-   [DANE Operational Guidance][rfc7671]

Compatibility
=============

Works with Prosody 0.9 until 0.11.

**Broken** since [trunk revision 756b8821007a](https://hg.prosody.im/trunk/rev/756b8821007a).

Known issues
============

-   A race condition between the DANE lookup and completion of the TLS
    handshake may cause a crash. This does not happen in **trunk**
    thanks to better async support.