diff --git a/postfix.nix b/postfix.nix
index f4bd48f..fb62478 100644
--- a/postfix.nix
+++ b/postfix.nix
@@ -200,6 +200,8 @@ in {
 
           auth_mechanisms = login plain
 
+          user_attrs = =user=%{ldap:cn}
+
           passdb {
             driver = ldap
             args = ${cfg.ldap-conf}