diff --git a/scripts/container/sync_barrier_donar b/scripts/container/sync_barrier_donar
index 24c9751..06d7354 100755
--- a/scripts/container/sync_barrier_donar
+++ b/scripts/container/sync_barrier_donar
@@ -2,7 +2,8 @@
 
 sleep 1
 echo "sync_barrier_start"
-nc -v --udp --source 127.0.0.1 --source-port $1 127.13.3.7 $2 --sh-exec '(while true; do sleep 1; echo a; done) & B=$!; read r; kill $B'
+nc -v --udp 127.13.3.7 $2 --sh-exec 'while true; do sleep 1; echo a; done' &
+nc -v --udp --listen 127.0.0.1 $1 --sh-exec 'killall -9 nc'
 echo "sync_barrier_release"
 sleep 10
 echo "sync_barrier_done"