diff --git a/ipset_linux.go b/ipset_linux.go
index 48b68d7..708f8f0 100644
--- a/ipset_linux.go
+++ b/ipset_linux.go
@@ -16,6 +16,8 @@ import (
 	"unsafe"
 )
 
+// netfilter netlink message types
+// https://github.com/torvalds/linux/blob/9e66317d3c92ddaab330c125dfe9d06eee268aff/include/uapi/linux/netfilter/nfnetlink.h#L56
 const NFNL_SUBSYS_IPSET = 6
 
 // http://git.netfilter.org/ipset/tree/include/libipset/linux_ip_set.h
diff --git a/redir_linux.go b/redir_linux.go
index 170397b..7335218 100644
--- a/redir_linux.go
+++ b/redir_linux.go
@@ -11,12 +11,13 @@ import (
 )
 
 const (
-	// from linux/include/uapi/linux/netfilter_ipv4.h
+	// SO_ORIGINAL_DST from linux/include/uapi/linux/netfilter_ipv4.h
 	SO_ORIGINAL_DST = 80
-	// from linux/include/uapi/linux/netfilter_ipv6/ip6_tables.h
+	// IP6T_SO_ORIGINAL_DST from linux/include/uapi/linux/netfilter_ipv6/ip6_tables.h
 	IP6T_SO_ORIGINAL_DST = 80
 )
 
+// RedirProxy struct
 type RedirProxy struct {
 	*Forwarder        // as client
 	sDialer    Dialer // dialer for server
diff --git a/server.go b/server.go
index ebc6ab6..a2c8581 100644
--- a/server.go
+++ b/server.go
@@ -10,9 +10,6 @@ import (
 type Server interface {
 	// ListenAndServe as proxy server, use only in server mode.
 	ListenAndServe()
-
-	// Serve
-	// Serve(c net.Conn)
 }
 
 // ServerFromURL parses url and get a Proxy