# KB-OPNsense - Bind LDAP Active directory 2025

<p class="callout info">Applicable à : OPNsense + Active directory (Windows Server 2025)</p>

### <span style="text-decoration: underline;">Symptôme(s)</span>

Impossible d'établir une connexion LDAP ou LDAPS depuis l'OPNsense.

[![image.png](https://docs.labs404.fr/uploads/images/gallery/2026-08/scaled-1680-/b42image.png)](https://docs.labs404.fr/uploads/images/gallery/2026-08/b42image.png)

[![image.png](https://docs.labs404.fr/uploads/images/gallery/2026-08/scaled-1680-/jjqimage.png)](https://docs.labs404.fr/uploads/images/gallery/2026-08/jjqimage.png)

---

### <span style="text-decoration: underline;">Problème</span>

Les nouvelles politiques de sécurités sur Windows Server 2025 sont trop restrictives et empêchent les clients linux / BSD de se connecter autrement qu'en LDAPS en ayant préalablement importé le certificat de la CA dans les trusts.

---

### <span style="text-decoration: underline;">Solutions</span>

1. Terminer la configuration LDAPS et importer le certificat de la CA dans '<span style="color: rgb(132, 63, 161);">***trust --&gt; certificates***</span>'
2. Appliquer la solution de contournement ci-dessous :

Sur le serveur Active Directory, modifier la GPO '<span style="color: rgb(132, 63, 161);">***Default Domain Policy***</span>'.

  
=Computer Configuration  
====Policies  
=======Windows Settings  
==========Security Settings  
=============Local Policies  
================Security Options  
===================Domain controller: LDAP server channel binding token requirements: "When Supported"  
===================Domain controller: LDAP server signing requirements: "None"  
===================Domain controller: LDAP server Enforce signing requirements: "Disabled"  
===================Network security: LDAP client encryption requirements: "Negotiate Sealing"  
===================Network security: LDAP client signing requirements: "Negotiate Signing"

---

### <span style="text-decoration: underline;">Sources</span>

<span style="background-color: rgb(251,238,184);">  
</span>

[Unable to connecto to LDAP (Windows Server 2025)](https://forum.opnsense.org/index.php?topic=45006.0)

[LDAP Authentication with Active Directory Windows Server 2025, bind fails | Netgate Forum](https://forum.netgate.com/topic/187453/ldap-authentication-with-active-directory-windows-server-2025-bind-fails/3)