diff --git a/src/adldap/samba/gp_manage.h b/src/adldap/samba/gp_manage.h
index 4a384d14..2a1e8fd1 100644
--- a/src/adldap/samba/gp_manage.h
+++ b/src/adldap/samba/gp_manage.h
@@ -29,6 +29,10 @@ extern "C" {
 #ifndef GP_MANAGE_H
 #define GP_MANAGE_H
 
+// time.h and unistd.h Are needed before including ndr.h when building against old samba (4.16)
+#include <time.h>
+#include <unistd.h>
+
 #include <ndr.h>
 #include <gen_ndr/security.h>
 #include <talloc.h>
diff --git a/src/adldap/samba/security_descriptor.h b/src/adldap/samba/security_descriptor.h
index 5dd5ce3f..09f1565b 100644
--- a/src/adldap/samba/security_descriptor.h
+++ b/src/adldap/samba/security_descriptor.h
@@ -30,6 +30,10 @@ extern "C" {
 #ifndef __SECURITY_DESCRIPTOR_H__
 #define __SECURITY_DESCRIPTOR_H__
 
+// time.h and unistd.h Are needed before including ndr.h when building against old samba (4.16)
+#include <time.h>
+#include <unistd.h>
+
 #include <ndr.h>
 #include <gen_ndr/security.h>
 
diff --git a/src/adldap/samba/src_older/dom_sid.c b/src/adldap/samba/src_older/dom_sid.c
index 96192773..aaa5666c 100644
--- a/src/adldap/samba/src_older/dom_sid.c
+++ b/src/adldap/samba/src_older/dom_sid.c
@@ -20,6 +20,10 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+// time.h and unistd.h Are needed before including gen_ndr/security.h when building against old samba (4.16)
+#include <time.h>
+#include <unistd.h>
+
 #include "replace.h"
 #include "util/data_blob.h"
 #include "gen_ndr/security.h"
diff --git a/src/adldap/samba/src_older/dom_sid.h b/src/adldap/samba/src_older/dom_sid.h
index 270c2ac0..4a3dee98 100644
--- a/src/adldap/samba/src_older/dom_sid.h
+++ b/src/adldap/samba/src_older/dom_sid.h
@@ -32,6 +32,10 @@
 extern "C" {
 #endif
 
+// time.h and unistd.h are needed before including gen_ndr/security.h when building against old samba (4.16)
+#include <time.h>
+#include <unistd.h>
+
 #include "replace.h"
 #include <talloc.h>
 #include "util/data_blob.h"
diff --git a/src/adldap/samba/src_older/ndr_misc.h b/src/adldap/samba/src_older/ndr_misc.h
index 14a122fc..1b0dea91 100644
--- a/src/adldap/samba/src_older/ndr_misc.h
+++ b/src/adldap/samba/src_older/ndr_misc.h
@@ -25,6 +25,10 @@
 extern "C" {
 #endif
 
+// time.h and unistd.h are needed before including ndr.h when building against old samba (4.16)
+#include <time.h>
+#include <unistd.h>
+
 #include <ndr.h>
 
 /* header auto-generated by pidl */
diff --git a/src/adldap/samba/src_older/ndr_security.h b/src/adldap/samba/src_older/ndr_security.h
index e715f9e3..4009d3b7 100644
--- a/src/adldap/samba/src_older/ndr_security.h
+++ b/src/adldap/samba/src_older/ndr_security.h
@@ -25,6 +25,10 @@
 extern "C" {
 #endif
 
+// time.h and unistd.h are needed before including ndr.h when building against old samba (4.16)
+#include <time.h>
+#include <unistd.h>
+
 #include <ndr.h>
 #include <gen_ndr/security.h>