diff --git a/scripts/base/frameworks/cluster/main.zeek b/scripts/base/frameworks/cluster/main.zeek
index 02c63562b6..f0ece62741 100644
--- a/scripts/base/frameworks/cluster/main.zeek
+++ b/scripts/base/frameworks/cluster/main.zeek
@@ -1,4 +1,4 @@
-##! A framework for establishing and controlling a cluster of Zeek instances.
+#hh#! A framework for establishing and controlling a cluster of Zeek instances.
 ##! In order to use the cluster framework, a script named
 ##! ``cluster-layout.zeek`` must exist somewhere in Zeek's script search path
 ##! which has a cluster definition of the :zeek:id:`Cluster::nodes` variable.
@@ -162,7 +162,7 @@ export {
 		## can specify a particular :rfc:`4007` ``zone_id``.
 		zone_id:      string      &default="";
 		## The port that this node will listen on for peer connections.
-		p:            port;
+		p:            port        &optional;
 		## Identifier for the interface a worker is sniffing.
 		interface:    string      &optional;
 		## Name of the manager node this node uses.  For workers and proxies.
diff --git a/scripts/base/frameworks/cluster/setup-connections.zeek b/scripts/base/frameworks/cluster/setup-connections.zeek
index 2abd57b142..7e470037a6 100644
--- a/scripts/base/frameworks/cluster/setup-connections.zeek
+++ b/scripts/base/frameworks/cluster/setup-connections.zeek
@@ -89,11 +89,15 @@ event zeek_init() &priority=-10
 	Broker::subscribe(nodeid_topic(Broker::node_id()));
 	Broker::subscribe(node_topic(node));
 
-	Broker::listen(Broker::default_listen_address,
-	               self$p,
-	               Broker::default_listen_retry);
+	if ( self?$p )
+		{
+		Broker::listen(Broker::default_listen_address,
+		               self$p,
+		               Broker::default_listen_retry);
+
+		Cluster::log(fmt("listening on %s:%s", Broker::default_listen_address, self$p));
+		}
 
-	Cluster::log(fmt("listening on %s:%s", Broker::default_listen_address, self$p));
 
 	switch ( self$node_type ) {
 	case MANAGER: