diff --git a/src/iterative-query.cpp b/src/iterative-query.cpp
new file mode 100644
index 0000000..989634a
--- /dev/null
+++ b/src/iterative-query.cpp
@@ -0,0 +1,141 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014, Regents of the University of California.
+ *
+ * This file is part of NDNS (Named Data Networking Domain Name Service).
+ * See AUTHORS.md for complete list of NDNS authors and contributors.
+ *
+ * NDNS is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NDNS 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NDNS, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "iterative-query.hpp"
+
+namespace ndn {
+namespace ndns {
+
+IterativeQuery::IterativeQuery(const Query& query)
+: m_step(IterativeQuery::NSQuery)
+, m_tryNum(0)
+, m_tryMax(2)
+, m_query(query)
+, m_finishedLabelNum(0)
+, m_rrLabelLen(1)
+, m_authZoneIndex(0)
+{
+}
+
+
+bool
+IterativeQuery::doTimeout()
+{
+  abort();
+  return false;
+}
+
+void
+IterativeQuery::abort(){
+  std::cout<<(*this);
+  std::cout<<std::endl;
+}
+
+void
+IterativeQuery::doData(Data& data)
+{
+  std::cout<<"[* -> *] resolve Data: "<<data.getName().toUri()<<std::endl;
+  Response re;
+  re.fromData(data);
+  std::cout<<re<<std::endl;
+
+  if (re.getResponseType() == Response::UNKNOWN)
+  {
+    std::cout<<"[* !! *] unknown content type and exit";
+    m_step = Abort;
+    abort();
+    return;
+  }
+  else if (re.getResponseType() == Response::NDNS_Nack)
+  {
+      if (m_step == NSQuery) {
+        //In fact, there are two different situations
+        //1st: /net/ndnsim/DNS/www/NS is nacked
+        //2st: /net/DNS/ndnsim/www/NS is nacked
+        m_step = RRQuery;
+
+      } else if (m_step == RRQuery)
+      {
+        m_step = AnswerStub;
+      }
+      m_lastResponse = re;
+  }
+  else if (re.getResponseType() == Response::NDNS_Auth)
+  { // need more specific info
+    m_rrLabelLen += 1;
+
+  }
+  else if (re.getResponseType() == Response::NDNS_Resp)
+  {// get the intermediate answer
+    if (m_step == NSQuery) {
+      //do nothing, step NSQuery
+      m_finishedLabelNum += m_rrLabelLen;
+      m_rrLabelLen = 1;
+      m_authZoneIndex = 0;
+      m_lastResponse = re;
+
+    } else if (m_step == RRQuery)
+    { // final resolver gets result back
+      m_step = AnswerStub;
+      m_lastResponse = re;
+    }
+
+    std::cout<<"get RRs: "<<m_lastResponse.getStringRRs()<<std::endl;
+  }
+
+}
+
+const Interest
+IterativeQuery::toLatestInterest()
+{
+  Query query = Query();
+  Name dstLabel = m_query.getRrLabel();
+
+  Name authZone = dstLabel.getPrefix(m_finishedLabelNum);
+
+  Name label;
+  if (m_step == RRQuery) {
+    label = dstLabel.getSubName(m_finishedLabelNum);
+  }
+  else {
+    label = dstLabel.getSubName(m_finishedLabelNum, m_rrLabelLen);
+  }
+  query.setAuthorityZone(authZone);
+  query.setRrLabel(label);
+
+  if (m_step == NSQuery)
+  {
+    query.setRrType(RR::NS);
+    query.setQueryType(Query::QUERY_DNS);
+  } else if (m_step == RRQuery)
+  {
+    query.setRrType(m_query.getRrType());
+    query.setQueryType(Query::QUERY_DNS);
+  } else if (m_step == AnswerStub)
+  {
+    query.setRrType(m_query.getRrType());
+    query.setQueryType(Query::QUERY_DNS);
+  }
+  Interest interest = query.toInterest();
+  //m_lastInterest = interest;
+
+  return interest;
+}
+
+} /* namespace ndns */
+} /* namespace ndn */