diff --git a/util.md b/util.md
index 1d2bb1e..75f1d61 100644
--- a/util.md
+++ b/util.md
@@ -1,4 +1,8 @@
 # package util // import "proxy/util"
+## CONSTANTS
+
+#### const (Out, In)
+Prefixes for traffic from (out) or to (in) VM
 ## Functions
 
 #### func DnsQueryDecode(data []byte, start int) (string, int)