diff --git a/src/net/asio-fwd.hpp b/src/net/asio-fwd.hpp
new file mode 100644
index 0000000..bda6b83
--- /dev/null
+++ b/src/net/asio-fwd.hpp
@@ -0,0 +1,47 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2017 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#ifndef NDN_NET_ASIO_FWD_HPP
+#define NDN_NET_ASIO_FWD_HPP
+
+#include <boost/version.hpp>
+
+#if BOOST_VERSION >= 106600
+
+#include <boost/asio/ts/netfwd.hpp>
+
+namespace boost {
+namespace asio {
+using io_service = io_context;
+} // namespace asio
+} // namespace boost
+
+#else
+
+namespace boost {
+namespace asio {
+class io_service;
+} // namespace asio
+} // namespace boost
+
+#endif // BOOST_VERSION >= 106600
+
+#endif // NDN_NET_ASIO_FWD_HPP
diff --git a/src/net/dns.hpp b/src/net/dns.hpp
index 79d9a10..5e22a84 100644
--- a/src/net/dns.hpp
+++ b/src/net/dns.hpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
@@ -22,17 +22,11 @@
 #ifndef NDN_NET_DNS_HPP
 #define NDN_NET_DNS_HPP
 
+#include "asio-fwd.hpp"
 #include "../util/time.hpp"
 
 #include <boost/asio/ip/address.hpp>
 
-// forward declaration
-namespace boost {
-namespace asio {
-class io_service;
-} // namespace asio
-} // namespace boost
-
 namespace ndn {
 namespace dns {
 
diff --git a/src/net/face-uri.hpp b/src/net/face-uri.hpp
index 12276cd..7461576 100644
--- a/src/net/face-uri.hpp
+++ b/src/net/face-uri.hpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2013-2017 Regents of the University of California,
  *                         Arizona Board of Regents,
  *                         Colorado State University,
@@ -28,6 +28,7 @@
 #ifndef NDN_NET_FACE_URI_HPP
 #define NDN_NET_FACE_URI_HPP
 
+#include "asio-fwd.hpp"
 #include "ethernet.hpp"
 #include "../util/time.hpp"
 
diff --git a/src/net/network-monitor.hpp b/src/net/network-monitor.hpp
index e6874a1..2441e3e 100644
--- a/src/net/network-monitor.hpp
+++ b/src/net/network-monitor.hpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
@@ -25,14 +25,10 @@
 #ifndef NDN_NET_NETWORK_MONITOR_HPP
 #define NDN_NET_NETWORK_MONITOR_HPP
 
+#include "asio-fwd.hpp"
 #include "network-interface.hpp"
-#include <vector>
 
-namespace boost {
-namespace asio {
-class io_service;
-} // namespace asio
-} // namespace boost
+#include <vector>
 
 namespace ndn {
 namespace net {