diff --git a/roles/sapp/templates/sapp.toml.j2 b/roles/sapp/templates/sapp.toml.j2
index e4a0400..dae751b 100644
--- a/roles/sapp/templates/sapp.toml.j2
+++ b/roles/sapp/templates/sapp.toml.j2
@@ -118,7 +118,7 @@ dictator_enable=0
     [stream.tcp]
     max=100000
     timeout=30
-    syn_mandatory=0
+    syn_mandatory=1
     reorder_pkt_max=5
     analyse_option_enabled=1
     tuple4_reuse_time_interval=30