# How to use kerberos authentication in combination with user LDAPS federation?

**URL:** <https://forum.keycloak.org/t/how-to-use-kerberos-authentication-in-combination-with-user-ldaps-federation/31160>\
**Category:** Miscellanaeous\
**Tags:** admin-console, authentication\
**Created:** [October 28, 2025, 4:22pm UTC](https://forum.keycloak.org/t/how-to-use-kerberos-authentication-in-combination-with-user-ldaps-federation/31160 "2025-10-28T16:22:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![spictera](https://avatars.discourse-cdn.com/v4/letter/s/ac91a4/32.png) [@spictera](https://forum.keycloak.org/u/spictera)\
**Post date:** [October 28, 2025, 4:22pm UTC](https://forum.keycloak.org/t/how-to-use-kerberos-authentication-in-combination-with-user-ldaps-federation/31160/1 "2025-10-28T16:22:54Z")

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Hi,

Is it possible to combine kerberos authentication with user federation?

So that when a kerberos authentication has been succeeded it should populate the groups for the user?

I tried to combine this, but get duplicate key for user XXX error; so I was unable to do this.

Tips?

Regards Tomas

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**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/keycloak/original/1X/eb342909d95cf32cbb7517610022c6a0046a9ffb.png) [@system](https://forum.keycloak.org/u/system)\
**Post date:** [April 26, 2026, 4:23pm UTC](https://forum.keycloak.org/t/how-to-use-kerberos-authentication-in-combination-with-user-ldaps-federation/31160/2 "2026-04-26T16:23:11Z")

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