diff --git a/bin/tests/system/notify/ns3/named.conf.in b/bin/tests/system/notify/ns3/named.conf.in
index 832043d9f6..65983e38a0 100644
--- a/bin/tests/system/notify/ns3/named.conf.in
+++ b/bin/tests/system/notify/ns3/named.conf.in
@@ -25,6 +25,8 @@ options {
 	recursion yes;
 	notify yes;
 	dnssec-validation no;
+
+	tcp-initial-timeout 150; # 15 seconds
 };
 
 zone "." {