diff --git a/src/zm_stream.cpp b/src/zm_stream.cpp
index 4e9a4da10..f50671338 100644
--- a/src/zm_stream.cpp
+++ b/src/zm_stream.cpp
@@ -18,6 +18,10 @@
 //
 
 #include <sys/un.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/file.h>
 
 #include "zm.h"
 #include "zm_mpeg.h"
@@ -290,7 +294,7 @@ void StreamBase::openComms()
 		snprintf( sock_path_lock, sizeof(sock_path_lock), "%s/zms-%06d.lock", config.path_socks, connkey);
 
         lock_fd = open(sock_path_lock, O_CREAT|O_WRONLY, S_IRUSR | S_IWUSR);
-        if (lock_fd <= 0 || flock(lock_fd, LOCK_SH|LOCK_NB) != 0)
+        if (lock_fd <= 0 || flock(lock_fd, LOCK_EX) != 0)
         {
             Error("Unable to lock sock lock file %s: %s", sock_path_lock, strerror(errno) );
 
@@ -299,7 +303,7 @@ void StreamBase::openComms()
         }
         else
         {
-            Debug( 1, "We have obtained a read lock on %s fd: %d", sock_path_lock, lock_fd);
+            Debug( 1, "We have obtained a lock on %s fd: %d", sock_path_lock, lock_fd);
         }