diff --git a/src/include/port.h b/src/include/port.h
index ae68d9c3c79..49b4d38131b 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -37,8 +37,9 @@ typedef SOCKET pgsocket;
 #define PGINVALID_SOCKET INVALID_SOCKET
 #endif
 
+/* if platform lacks socklen_t, we assume this will work */
 #ifndef HAVE_SOCKLEN_T
-typedef int socklen_t;
+typedef unsigned int socklen_t;
 #endif
 
 /* non-blocking */