diff --git a/e_os.h b/e_os.h
index df72c7454a..78753de970 100644
--- a/e_os.h
+++ b/e_os.h
@@ -259,6 +259,18 @@ extern "C" {
 	*/
 #      define _WIN32_WINNT 0x0400
 #    endif
+#    if !defined(OPENSSL_NO_SOCK) && defined(_WIN32_WINNT)
+       /*
+        * Just like defining _WIN32_WINNT including winsock2.h implies
+        * certain "discipline" for maintaing [broad] binary compatibility.
+        * As long as structures are invariant among Winsock versions,
+        * it's sufficient to check for specific Winsock2 API availability
+        * at run-time [DSO_global_lookup is recommended]...
+        */
+#      include <winsock2.h>
+#      include <ws2tcpip.h>
+       /* yes, they have to be #included prior <windows.h> */
+#    endif
 #    include <windows.h>
 #    include <stddef.h>
 #    include <errno.h>