diff --git a/bin/tests/system/start.pl b/bin/tests/system/start.pl
index 07b699c702..6380ccb154 100755
--- a/bin/tests/system/start.pl
+++ b/bin/tests/system/start.pl
@@ -191,7 +191,7 @@ sub start_server {
 			close FH;
 			$command .= "$options";
 		} else {
-			$command .= "-D $server ";
+			$command .= "-D $test-$server ";
 			$command .= "-X named.lock ";
 			$command .= "-m record,size,mctx ";
 			$command .= "-T clienttest ";