diff --git a/source4/rpc_server/backupkey/dcesrv_backupkey.c b/source4/rpc_server/backupkey/dcesrv_backupkey.c
index 5d182ea4211..0eda3ce7018 100644
--- a/source4/rpc_server/backupkey/dcesrv_backupkey.c
+++ b/source4/rpc_server/backupkey/dcesrv_backupkey.c
@@ -62,8 +62,7 @@ static NTSTATUS set_lsa_secret(TALLOC_CTX *mem_ctx,
 	TALLOC_CTX *frame = talloc_stackframe();
 	struct ldb_message *msg;
 	struct ldb_result *res;
-	struct ldb_dn *domain_dn;
-	struct ldb_dn *system_dn;
+	struct ldb_dn *system_dn = NULL;
 	struct ldb_val val;
 	int ret;
 	char *name2;
@@ -73,12 +72,6 @@ static NTSTATUS set_lsa_secret(TALLOC_CTX *mem_ctx,
 		NULL
 	};
 
-	domain_dn = ldb_get_default_basedn(ldb);
-	if (!domain_dn) {
-		talloc_free(frame);
-		return NT_STATUS_INTERNAL_ERROR;
-	}
-
 	msg = ldb_msg_new(frame);
 	if (msg == NULL) {
 		talloc_free(frame);
@@ -95,12 +88,17 @@ static NTSTATUS set_lsa_secret(TALLOC_CTX *mem_ctx,
 	 * * taillor the function to the particular needs of backup protocol
 	 */
 
-	system_dn = samdb_search_dn(ldb, msg, domain_dn, "(&(objectClass=container)(cn=System))");
+	system_dn = ldb_dn_copy(frame, ldb_get_default_basedn(ldb));
 	if (system_dn == NULL) {
 		talloc_free(frame);
 		return NT_STATUS_NO_MEMORY;
 	}
 
+	if (!ldb_dn_add_child_fmt(system_dn, "CN=System")) {
+		talloc_free(frame);
+		return NT_STATUS_NO_MEMORY;
+	}
+
 	name2 = talloc_asprintf(msg, "%s Secret", name);
 	if (name2 == NULL) {
 		talloc_free(frame);
@@ -186,8 +184,7 @@ static NTSTATUS get_lsa_secret(TALLOC_CTX *mem_ctx,
 {
 	TALLOC_CTX *tmp_mem;
 	struct ldb_result *res;
-	struct ldb_dn *domain_dn;
-	struct ldb_dn *system_dn;
+	struct ldb_dn *system_dn = NULL;
 	const struct ldb_val *val;
 	uint8_t *data;
 	const char *attrs[] = {
@@ -199,22 +196,22 @@ static NTSTATUS get_lsa_secret(TALLOC_CTX *mem_ctx,
 	lsa_secret->data = NULL;
 	lsa_secret->length = 0;
 
-	domain_dn = ldb_get_default_basedn(ldb);
-	if (!domain_dn) {
-		return NT_STATUS_INTERNAL_ERROR;
-	}
-
 	tmp_mem = talloc_new(mem_ctx);
 	if (tmp_mem == NULL) {
 		return NT_STATUS_NO_MEMORY;
 	}
 
-	system_dn = samdb_search_dn(ldb, tmp_mem, domain_dn, "(&(objectClass=container)(cn=System))");
+	system_dn = ldb_dn_copy(tmp_mem, ldb_get_default_basedn(ldb));
 	if (system_dn == NULL) {
 		talloc_free(tmp_mem);
 		return NT_STATUS_NO_MEMORY;
 	}
 
+	if (!ldb_dn_add_child_fmt(system_dn, "CN=System")) {
+		talloc_free(tmp_mem);
+		return NT_STATUS_NO_MEMORY;
+	}
+
 	ret = ldb_search(ldb, mem_ctx, &res, system_dn, LDB_SCOPE_SUBTREE, attrs,
 			   "(&(cn=%s Secret)(objectclass=secret))",
 			   ldb_binary_encode_string(tmp_mem, name));
diff --git a/source4/rpc_server/lsa/lsa_init.c b/source4/rpc_server/lsa/lsa_init.c
index 689634b9706..62aa638f4f5 100644
--- a/source4/rpc_server/lsa/lsa_init.c
+++ b/source4/rpc_server/lsa/lsa_init.c
@@ -146,10 +146,13 @@ NTSTATUS dcesrv_lsa_get_policy_state(struct dcesrv_call_state *dce_call,
 
 	/* work out the system_dn - useful for so many calls its worth
 	   fetching here */
-	state->system_dn = samdb_search_dn(state->sam_ldb, state,
-					   state->domain_dn, "(&(objectClass=container)(cn=System))");
-	if (!state->system_dn) {
-		return NT_STATUS_NO_SUCH_DOMAIN;		
+	state->system_dn = ldb_dn_copy(state, state->domain_dn);
+	if (state->system_dn == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	if (!ldb_dn_add_child_fmt(state->system_dn, "CN=System")) {
+		return NT_STATUS_NO_MEMORY;
 	}
 
 	state->builtin_sid = dom_sid_parse_talloc(state, SID_BUILTIN);
diff --git a/source4/rpc_server/netlogon/dcerpc_netlogon.c b/source4/rpc_server/netlogon/dcerpc_netlogon.c
index dc2167f08b2..bb1a08be9db 100644
--- a/source4/rpc_server/netlogon/dcerpc_netlogon.c
+++ b/source4/rpc_server/netlogon/dcerpc_netlogon.c
@@ -3941,11 +3941,13 @@ static WERROR fill_trusted_domains_array(TALLOC_CTX *mem_ctx,
 		return WERR_INVALID_FLAGS;
 	}
 
-	system_dn = samdb_search_dn(sam_ctx, mem_ctx,
-				    ldb_get_default_basedn(sam_ctx),
-				    "(&(objectClass=container)(cn=System))");
-	if (!system_dn) {
-		return WERR_GEN_FAILURE;
+	system_dn = ldb_dn_copy(mem_ctx, ldb_get_default_basedn(sam_ctx));
+	if (system_dn == NULL) {
+		return WERR_NOT_ENOUGH_MEMORY;
+	}
+
+	if (!ldb_dn_add_child_fmt(system_dn, "CN=System")) {
+		return WERR_NOT_ENOUGH_MEMORY;
 	}
 
 	ret = gendb_search(sam_ctx, mem_ctx, system_dn,