diff --git a/include/types/proxy.h b/include/types/proxy.h
index b33b634..7331ca3 100644
--- a/include/types/proxy.h
+++ b/include/types/proxy.h
@@ -82,7 +82,7 @@
 #define PR_O_DISPATCH   0x00000040      /* use dispatch mode */
 /* unused: 0x00000080 */
 #define PR_O_FWDFOR     0x00000100      /* conditionally insert x-forwarded-for with client address */
-/* unused: 0x00000200 */
+#define PR_O_IGNORE_PRB 0x00000200      /* ignore empty requests (aborts and timeouts) */
 #define PR_O_NULLNOLOG  0x00000400      /* a connect without request will not be logged */
 /* unused: 0x0800, 0x1000 */
 #define PR_O_FF_ALWAYS  0x00002000      /* always set x-forwarded-for */