diff --git a/dns_client.h b/dns_client.h
new file mode 100644
index 0000000..dd47784
--- /dev/null
+++ b/dns_client.h
@@ -0,0 +1,87 @@
+// Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SHILL_DNS_CLIENT_
+#define SHILL_DNS_CLIENT_
+
+#include <string>
+#include <vector>
+
+#include <base/callback_old.h>
+#include <base/memory/scoped_ptr.h>
+#include <base/task.h>
+#include <gtest/gtest_prod.h>  // for FRIEND_TEST
+
+#include "shill/event_dispatcher.h"
+#include "shill/ip_address.h"
+#include "shill/refptr_types.h"
+
+struct hostent;
+
+namespace shill {
+
+class Ares;
+class Time;
+struct DNSClientState;
+
+// Implements a DNS resolution client that can run asynchronously
+class DNSClient {
+ public:
+  static const int kDefaultTimeoutMS;
+  static const char kErrorNoData[];
+  static const char kErrorFormErr[];
+  static const char kErrorServerFail[];
+  static const char kErrorNotFound[];
+  static const char kErrorNotImp[];
+  static const char kErrorRefused[];
+  static const char kErrorBadQuery[];
+  static const char kErrorNetRefused[];
+  static const char kErrorTimedOut[];
+  static const char kErrorUnknown[];
+
+  DNSClient(IPAddress::Family family,
+            const std::string &interface_name,
+            const std::vector<std::string> &dns_servers,
+            int timeout_ms,
+            EventDispatcher *dispatcher,
+            Callback1<bool>::Type *callback);
+  ~DNSClient();
+
+  bool Start(const std::string &hostname);
+  void Stop();
+  const IPAddress &address() const { return address_; }
+  const std::string &error() const { return error_; }
+
+ private:
+  friend class DNSClientTest;
+
+  void HandleDNSRead(int fd);
+  void HandleDNSWrite(int fd);
+  void HandleTimeout();
+  void ReceiveDNSReply(int status, struct hostent *hostent);
+  static void ReceiveDNSReplyCB(void *arg, int status, int timeouts,
+                                struct hostent *hostent);
+  bool RefreshHandles();
+
+  IPAddress address_;
+  std::string interface_name_;
+  std::vector<std::string> dns_servers_;
+  EventDispatcher *dispatcher_;
+  Callback1<bool>::Type *callback_;
+  int timeout_ms_;
+  bool running_;
+  std::string error_;
+  scoped_ptr<DNSClientState> resolver_state_;
+  scoped_ptr<Callback1<int>::Type> read_callback_;
+  scoped_ptr<Callback1<int>::Type> write_callback_;
+  ScopedRunnableMethodFactory<DNSClient> task_factory_;
+  Ares *ares_;
+  Time *time_;
+
+  DISALLOW_COPY_AND_ASSIGN(DNSClient);
+};
+
+}  // namespace shill
+
+#endif  // SHILL_DNS_CLIENT_