diff --git a/udp.go b/udp.go
index f5fe64b..02dbfda 100644
--- a/udp.go
+++ b/udp.go
@@ -47,7 +47,13 @@ func (s *UDPConn) WriteTo(b []byte, addr net.Addr) (int, error) {
 
 	atyp, host, port := socksAddr.Socks()
 	datagram := NewDatagram(atyp, host, port, b)
-	return s.PacketConn.WriteTo(datagram.Bytes(), s.ServerAddr)
+
+	n, err := s.PacketConn.WriteTo(datagram.Bytes(), s.ServerAddr)
+	if n < 10 {
+		n = 10
+	}
+
+	return n - 10, err
 }
 
 func (s *UDPConn) Write(b []byte) (int, error) {