diff --git a/userspace/libraries/LibC/include/netinet/in.h b/userspace/libraries/LibC/include/netinet/in.h
index 25104bee..0098a2bd 100644
--- a/userspace/libraries/LibC/include/netinet/in.h
+++ b/userspace/libraries/LibC/include/netinet/in.h
@@ -62,6 +62,7 @@ enum
 #define IPV6_V6ONLY IPV6_V6ONLY
 };
 
+#define IN_LOOPBACKNET 127
 #define IN_MULTICAST(a) (((in_addr_t)(a) & 0xF0000000) == 0xE0000000)
 
 #define INADDR_ANY			0