diff --git a/hosts/hedgedoc/default.nix b/hosts/hedgedoc/default.nix
index d21b5620..2dbfbc94 100644
--- a/hosts/hedgedoc/default.nix
+++ b/hosts/hedgedoc/default.nix
@@ -1,4 +1,4 @@
-{ config, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 {
   c3d2.deployment.server = "server10";
@@ -28,6 +28,7 @@
         };
         defaultPermission = "freely";
         domain = "hedgedoc.c3d2.de";
+        ldap.searchFilter = lib.mkForce "(&(&(objectclass=person)(|(uid={{username}})(mail={{username}})))(isMemberOf=cn=hedgedoc,${config.security.ldap.roleBaseDN}))";
         loglevel = "warn";
         protocolUseSSL = true;
         sessionSecret = "$sessionSecret";