diff --git a/xwords4/common/comms.c b/xwords4/common/comms.c
index e1a71f7da..c956a54a6 100644
--- a/xwords4/common/comms.c
+++ b/xwords4/common/comms.c
@@ -715,7 +715,7 @@ comms_getInitialAddr( CommsAddrRec* addr )
 #if defined  XWFEATURE_RELAY
     addr->conType = COMMS_CONN_RELAY; /* for temporary ease in debugging */
     addr->u.ip_relay.ipAddr = 0L; /* force 'em to set it */
-    addr->u.ip_relay.port = 10999;
+    addr->u.ip_relay.port = RELAY_PORT_DEFAULT;
     {
         char* name = RELAY_NAME_DEFAULT;
         char* room = RELAY_ROOM_DEFAULT;
diff --git a/xwords4/common/comtypes.h b/xwords4/common/comtypes.h
index 9f60edfbf..c6a7c215f 100644
--- a/xwords4/common/comtypes.h
+++ b/xwords4/common/comtypes.h
@@ -171,6 +171,9 @@ typedef struct CommonPrefs {
 #ifndef RELAY_ROOM_DEFAULT
 # define RELAY_ROOM_DEFAULT "Room 1"
 #endif
+#ifndef RELAY_PORT_DEFAULT
+# define RELAY_PORT_DEFAULT 10999
+#endif
 
 #ifdef MEM_DEBUG
 # define XP_MALLOC(pool,nbytes) \