diff --git a/include/windivert_device.h b/include/windivert_device.h
index 36fdbf4..6f170ec 100644
--- a/include/windivert_device.h
+++ b/include/windivert_device.h
@@ -131,18 +131,14 @@
  * WinDivert flags.
  */
 #define WINDIVERT_FLAGS_ALL                                                 \
-    (WINDIVERT_FLAG_SNIFF | WINDIVERT_FLAG_DROP | WINDIVERT_FLAG_PASSTHRU | \
+    (WINDIVERT_FLAG_SNIFF | WINDIVERT_FLAG_DROP |                           \
      WINDIVERT_FLAG_NO_CHECKSUM)
 #define WINDIVERT_FLAGS_EXCLUDE(flags, flag1, flag2)                        \
     (((flags) & ((flag1) | (flag2))) != ((flag1) | (flag2)))
 #define WINDIVERT_FLAGS_VALID(flags)                                        \
     ((((flags) & ~WINDIVERT_FLAGS_ALL) == 0) &&                             \
      WINDIVERT_FLAGS_EXCLUDE(flags, WINDIVERT_FLAG_SNIFF,                   \
-        WINDIVERT_FLAG_DROP) &&                                             \
-     WINDIVERT_FLAGS_EXCLUDE(flags, WINDIVERT_FLAG_SNIFF,                   \
-        WINDIVERT_FLAG_PASSTHRU) &&                                         \
-     WINDIVERT_FLAGS_EXCLUDE(flags, WINDIVERT_FLAG_DROP,                    \
-        WINDIVERT_FLAG_PASSTHRU))
+        WINDIVERT_FLAG_DROP))
 /*
  * WinDivert priorities.
  */