[3947] Removed the new-leases-on-renew config parameter.

This change removes ability to disable allocation new leases new
Renew/Rebind, specified in RFC7550. The behavior specified in this
RFC is the only supported behavior.

17 files changed, 156 insertions, 868 deletions

diff --git a/src/bin/dhcp6/dhcp6.spec b/src/bin/dhcp6/dhcp6.spec
index e577e889f3..e0fa45be45 100644
--- a/src/bin/dhcp6/dhcp6.spec
+++ b/src/bin/dhcp6/dhcp6.spec
@@ -62,12 +62,6 @@
         "item_default": 4000
       },
 
-      { "item_name": "new-leases-on-renew",
-        "item_type": "boolean",
-        "item_optional": true,
-        "item_default": true
-      },
-
       { "item_name": "option-def",
         "item_type": "list",
         "item_optional": false,
diff --git a/src/bin/dhcp6/dhcp6_messages.mes b/src/bin/dhcp6/dhcp6_messages.mes
index d0d7aa15ec..acdc88884f 100644
--- a/src/bin/dhcp6/dhcp6_messages.mes
+++ b/src/bin/dhcp6/dhcp6_messages.mes
@@ -224,24 +224,6 @@ as a result of receiving SIGHUP signal.
 This is an error message logged when the dynamic reconfiguration of the
 DHCP server failed.
 
-% DHCP6_EXTEND_NA_UNKNOWN %1: received unknown IA_NA with iaid=%2 in subnet %3
-This warning message is printed when client attempts to extend the lease
-for the address (in the IA_NA option) but no such lease is known by the server.
-It typically means that client has attempted to use its lease past its
-lifetime: causes of this include a adjustment of the client's date/time
-setting or poor support on the client for sleep/recovery. A properly
-implemented client will recover from such a situation by restarting the
-lease allocation process after receiving a negative reply from the server.
-The first argument includes the client and the transaction identification
-information. The second argument holds IAID. The third argument holds the
-subnet information.
-
-An alternative cause could be that the server has lost its database
-recently and does not recognize its well-behaving clients. This is more
-probable if you see many such messages. Clients will recover from this,
-but they will most likely get a different IP addresses and experience
-a brief service interruption.
-
 % DHCP6_HOOKS_LIBS_RELOAD_FAIL reload of hooks libraries failed
 A "libreload" command was issued to reload the hooks libraries but for
 some reason the reload failed.  Other error messages issued from the
diff --git a/src/bin/dhcp6/dhcp6_srv.cc b/src/bin/dhcp6/dhcp6_srv.cc
index 2f214ee09a..82cb272ebb 100644
--- a/src/bin/dhcp6/dhcp6_srv.cc
+++ b/src/bin/dhcp6/dhcp6_srv.cc
@@ -1721,7 +1721,6 @@ Dhcpv6Srv::extendIA_NA(const Pkt6Ptr& query, const Pkt6Ptr& answer,
     ctx.ia_rsp_ = ia_rsp;
     ctx.hwaddr_ = orig_ctx.hwaddr_;
     ctx.host_ = orig_ctx.host_;
-    ctx.allow_new_leases_in_renewals_ = subnet->getAllocLeasesOnRenew();
 
     // Extract the addresses that the client is trying to obtain.
     OptionCollection addrs = ia->getOptions();
@@ -1802,34 +1801,12 @@ Dhcpv6Srv::extendIA_NA(const Pkt6Ptr& query, const Pkt6Ptr& answer,
     // All is left is to insert the status code.
     if (leases.empty()) {
 
-        // We did not assign any address to the client. Depending on whether the
-        // server is configured to allocate new leases during the Renew or
-        // Rebind we will have to send a different status code. If the server
-        // is configured to allocate new leases for the Renew and Rebind, the
-        // status code will be NoAddressAvail. If the server is not configured
-        // to allocate prefixes for the renewing client, the status code will
-        // be NoBinding, or perhaps the message will be dropped if this is the
-        // Rebind case.
-        if (!subnet->getAllocLeasesOnRenew()) {
-            ia_rsp->addOption(createStatusCode(*query, *ia_rsp,
-                                               STATUS_NoBinding,
-                                               "Sorry, no known NA leases for"
-                                               " this duid/iaid/subnet."));
-            LOG_DEBUG(lease_logger, DBG_DHCP6_DETAIL, DHCP6_EXTEND_NA_UNKNOWN)
-                .arg(query->getLabel())
-                .arg(ia->getIAID())
-                .arg(subnet->toText());
-
-
-        } else {
-            // The server is configured to allocate new leases for the
-            // renewing client, but it could not allocate anything at this
-            // time. The status code should be NoAddrsAvail, per RFC7550.
-            ia_rsp->addOption(createStatusCode(*query, *ia_rsp,
-                                               STATUS_NoAddrsAvail,
-                                               "Sorry, no addresses could be"
-                                               " assigned at this time."));
-        }
+        // The server wasn't able allocate new lease and renew an exising
+        // lease. In that case, the server sends NoAddrsAvail per RFC7550.
+        ia_rsp->addOption(createStatusCode(*query, *ia_rsp,
+                                           STATUS_NoAddrsAvail,
+                                           "Sorry, no addresses could be"
+                                           " assigned at this time."));
     }
 
     return (ia_rsp);
@@ -1894,7 +1871,6 @@ Dhcpv6Srv::extendIA_PD(const Pkt6Ptr& query,
     ctx.ia_rsp_ = ia_rsp;
     ctx.hwaddr_ = orig_ctx.hwaddr_;
     ctx.host_ = orig_ctx.host_;
-    ctx.allow_new_leases_in_renewals_ = subnet->getAllocLeasesOnRenew();
 
     // Extract prefixes that the client is trying to renew.
     OptionCollection addrs = ia->getOptions();
@@ -1963,47 +1939,12 @@ Dhcpv6Srv::extendIA_PD(const Pkt6Ptr& query,
     // All is left is to insert the status code.
     if (leases.empty()) {
 
-        // We did not assign any prefix to the client. Depending on whether the
-        // server is configured to allocate new leases during the Renew or
-        // Rebind we will have to send a different status code. If the server
-        // is configured to allocate new leases for the Renew and Rebind, the
-        // status code will be NoPrefixAvail. If the server is not configured
-        // to allocate prefixes for the renewing client, the status code will
-        // be NoBinding, or perhaps the message will be dropped if this is the
-        // Rebind case.
-        if (!subnet->getAllocLeasesOnRenew()) {
-            // The server is not configured to allocate new leases, so return
-            // the NoBinding for the Renew, and drop the message for the
-            // Rebind. There is also a detailed comment for the Rebind case
-            // further on.
-            if (query->getType() == DHCPV6_RENEW) {
-                ia_rsp->addOption(createStatusCode(*query, *ia_rsp,
-                                                   STATUS_NoBinding,
-                                                   "Sorry, no known PD leases for"
-                                                   " this duid/iaid/subnet."));
-            } else {
-                // Per RFC3633, section 12.2, if there is no binding and we are
-                // processing Rebind, the message has to be discarded (assuming that
-                // the server doesn't know if the prefix in the IA_PD option is
-                // appropriate for the client's link). The exception being thrown
-                // here should propagate to the main loop and cause the message to
-                // be discarded.
-                isc_throw(DHCPv6DiscardMessageError, "no binding found for the"
-                          " DUID=" << duid->toText() << ", IAID="
-                          << ia->getIAID() << ", subnet="
-                          << subnet->toText() << " when processing a Rebind"
-                          " message with IA_PD option");
-            }
-
-        } else {
-            // The server is configured to allocate new leases for the
-            // renewing client, but it could not allocate anything at this
-            // time. The status code should be NoPrefixAvail, per RFC7550.
-            ia_rsp->addOption(createStatusCode(*query, *ia_rsp,
-                                               STATUS_NoPrefixAvail,
-                                               "Sorry, no prefixes could be"
-                                               " assigned at this time."));
-        }
+        // The server wasn't able allocate new lease and renew an exising
+        // lease. In that case, the server sends NoPrefixAvail per RFC7550.
+        ia_rsp->addOption(createStatusCode(*query, *ia_rsp,
+                                           STATUS_NoPrefixAvail,
+                                           "Sorry, no prefixes could be"
+                                           " assigned at this time."));
     }
 
     return (ia_rsp);
diff --git a/src/bin/dhcp6/json_config_parser.cc b/src/bin/dhcp6/json_config_parser.cc
index f7c4efdc60..29f64f19de 100644
--- a/src/bin/dhcp6/json_config_parser.cc
+++ b/src/bin/dhcp6/json_config_parser.cc
@@ -475,16 +475,13 @@ protected:
 
         // Gather boolean parameters values.
         bool rapid_commit = boolean_values_->getOptionalParam("rapid-commit", false);
-        bool alloc_leases_on_renew = globalContext()->
-            boolean_values_->getOptionalParam("new-leases-on-renew", true);
 
         std::ostringstream output;
         output << addr << "/" << static_cast<int>(len)
                << " with params t1=" << t1 << ", t2="
                << t2 << ", preferred-lifetime=" << pref
                << ", valid-lifetime=" << valid
-               << ", rapid-commit is " << (rapid_commit ? "enabled" : "disabled")
-               << ", new-leases-on-renew is " << (alloc_leases_on_renew ? "enabled" : "disabled");
+               << ", rapid-commit is " << (rapid_commit ? "enabled" : "disabled");
 
 
         LOG_INFO(dhcp6_logger, DHCP6_CONFIG_NEW_SUBNET).arg(output.str());
@@ -502,8 +499,6 @@ protected:
 
         // Enable or disable Rapid Commit option support for the subnet.
         subnet6->setRapidCommit(rapid_commit);
-        // Enable or disable allocation of the new leases for the Renew or/and Rebind message.
-        subnet6->setAllocLeasesOnRenew(alloc_leases_on_renew);
 
         // Try setting up client class (if specified)
         try {
@@ -700,8 +695,6 @@ namespace dhcp {
         parser = new RSOOListConfigParser(config_id);
     } else if (config_id.compare("control-socket") == 0) {
         parser = new ControlSocketParser(config_id);
-    } else if (config_id.compare("new-leases-on-renew") == 0) {
-        parser = new BooleanParser(config_id, globalContext()->boolean_values_);
     } else {
         isc_throw(DhcpConfigError,
                 "unsupported global configuration parameter: "
diff --git a/src/bin/dhcp6/tests/config_parser_unittest.cc b/src/bin/dhcp6/tests/config_parser_unittest.cc
index 5b905c2d10..46f6d91601 100644
--- a/src/bin/dhcp6/tests/config_parser_unittest.cc
+++ b/src/bin/dhcp6/tests/config_parser_unittest.cc
@@ -531,37 +531,6 @@ public:
         CfgMgr::instance().clear();
     }
 
-    /// @brief Test the 'new-leases-on-renew' configuration flag.
-    ///
-    /// @param config Server configuration, possibly including the
-    /// 'new-leases-on-renew' parameter.
-    /// @param exp_alloc_leases_on_renew Expected value of the flag
-    void testAllocLeasesOnRenew(const std::string& config,
-                                const bool exp_alloc_leases_on_renew) {
-        // Clear any existing configuration.
-        CfgMgr::instance().clear();
-
-        // Configure the server.
-        ElementPtr json = Element::fromJSON(config);
-
-        // Make sure that the configuration was successful.
-        ConstElementPtr status;
-        EXPECT_NO_THROW(status = configureDhcp6Server(srv_, json));
-        checkResult(status, 0);
-
-        // Get the subnet.
-        Subnet6Ptr subnet = CfgMgr::instance().getStagingCfg()->getCfgSubnets6()->
-            selectSubnet(IOAddress("2001:db8:1::5"), classify_);
-        ASSERT_TRUE(subnet);
-
-        // Check the flag against the expected value.
-        EXPECT_EQ(exp_alloc_leases_on_renew, subnet->getAllocLeasesOnRenew());
-
-        // Clear any existing configuration.
-        CfgMgr::instance().clear();
-    }
-
-
     int rcode_;          ///< Return code (see @ref isc::config::parseAnswer)
     Dhcpv6Srv srv_;      ///< Instance of the Dhcp6Srv used during tests
     ConstElementPtr comment_; ///< Comment (see @ref isc::config::parseAnswer)
@@ -1203,55 +1172,6 @@ TEST_F(Dhcp6ParserTest, subnetRapidCommit) {
     }
 }
 
-// This test checks the configuration of the Rapid Commit option
-// support for the subnet.
-TEST_F(Dhcp6ParserTest, subnetAllocLeasesOnRenew) {
-    {
-        // new-leases-on-renew implicitly set to false.
-        SCOPED_TRACE("Default setting for new-leases-on-renew");
-        testAllocLeasesOnRenew("{ \"preferred-lifetime\": 3000,"
-                               "\"rebind-timer\": 2000, "
-                               "\"renew-timer\": 1000, "
-                               "\"subnet6\": [ { "
-                               "    \"pools\": [ { \"pool\": \"2001:db8:1::1 - "
-                               "2001:db8:1::ffff\" } ],"
-                               "    \"subnet\": \"2001:db8:1::/64\" } ],"
-                               "\"valid-lifetime\": 4000 }",
-                               true);
-    }
-
-    {
-        // new-leases-on-renew explicitly set to true.
-        SCOPED_TRACE("Enable new-leases-on-renew");
-        testAllocLeasesOnRenew("{ \"preferred-lifetime\": 3000,"
-                               "\"rebind-timer\": 2000, "
-                               "\"renew-timer\": 1000, "
-                               "\"new-leases-on-renew\": True,"
-
-                               "\"subnet6\": [ { "
-                               "    \"pools\": [ { \"pool\": \"2001:db8:1::1 - "
-                               "2001:db8:1::ffff\" } ],"
-                               "    \"subnet\": \"2001:db8:1::/64\" } ],"
-                               "\"valid-lifetime\": 4000 }",
-                               true);
-    }
-
-    {
-        // new-leases-on-renew explicitly set to false.
-        SCOPED_TRACE("Disable new-leases-on-renew");
-        testAllocLeasesOnRenew("{ \"preferred-lifetime\": 3000,"
-                               "\"rebind-timer\": 2000, "
-                               "\"renew-timer\": 1000, "
-                               "\"new-leases-on-renew\": False,"
-                               "\"subnet6\": [ { "
-                               "    \"pools\": [ { \"pool\": \"2001:db8:1::1 - "
-                               "2001:db8:1::ffff\" } ],"
-                               "    \"subnet\": \"2001:db8:1::/64\" } ],"
-                               "\"valid-lifetime\": 4000 }",
-                               false);
-    }
-}
-
 // This test checks that multiple pools can be defined and handled properly.
 // The test defines 2 subnets, each with 2 pools.
 TEST_F(Dhcp6ParserTest, multiplePools) {
diff --git a/src/bin/dhcp6/tests/dhcp6_client.cc b/src/bin/dhcp6/tests/dhcp6_client.cc
index 442689ded6..503f973b3d 100644
--- a/src/bin/dhcp6/tests/dhcp6_client.cc
+++ b/src/bin/dhcp6/tests/dhcp6_client.cc
@@ -94,7 +94,9 @@ Dhcp6Client::Dhcp6Client() :
     use_rapid_commit_(false),
     address_hint_(),
     prefix_hint_(),
-    fqdn_() {
+    fqdn_(),
+    na_iaid_(1234),
+    pd_iaid_(5678) {
 }
 
 Dhcp6Client::Dhcp6Client(boost::shared_ptr<NakedDhcpv6Srv>& srv) :
@@ -113,7 +115,9 @@ Dhcp6Client::Dhcp6Client(boost::shared_ptr<NakedDhcpv6Srv>& srv) :
     use_rapid_commit_(false),
     address_hint_(),
     prefix_hint_(),
-    fqdn_() {
+    fqdn_(),
+    na_iaid_(1234),
+    pd_iaid_(5678) {
 }
 
 void
@@ -243,11 +247,11 @@ Dhcp6Client::appendFQDN() {
 void
 Dhcp6Client::appendRequestedIAs(const Pkt6Ptr& query) const {
     if (use_na_) {
-        conditionallyAppendRequestedIA(query, D6O_IA_NA, 1234);
+        conditionallyAppendRequestedIA(query, D6O_IA_NA, na_iaid_);
     }
 
     if (use_pd_) {
-        conditionallyAppendRequestedIA(query, D6O_IA_PD, 5678);
+        conditionallyAppendRequestedIA(query, D6O_IA_PD, pd_iaid_);
     }
 }
 
@@ -445,9 +449,9 @@ Dhcp6Client::doInfRequest() {
     // IA_NA, IA_TA and IA_PD options are not allowed in INF-REQUEST,
     // but hey! Let's test it.
     if (use_na_) {
-        // Insert IA_NA option with iaid=1234.
+        // Insert IA_NA option.
         context_.query_->addOption(Option6IAPtr(new Option6IA(D6O_IA_NA,
-                                                              1234)));
+                                                              na_iaid_)));
     }
 
     // IA-PD is also not allowed. So it may be useful in testing, too.
diff --git a/src/bin/dhcp6/tests/dhcp6_client.h b/src/bin/dhcp6/tests/dhcp6_client.h
index 68dffe0dec..ffcee8b673 100644
--- a/src/bin/dhcp6/tests/dhcp6_client.h
+++ b/src/bin/dhcp6/tests/dhcp6_client.h
@@ -439,8 +439,10 @@ public:
     ///
     /// @param use Parameter which 'true' value indicates that client should
     /// request address assignment.
-    void useNA(const bool use = true) {
+    /// @param iaid IAID to be used in the IA_NA.
+    void useNA(const bool use = true, const uint32_t iaid = 1234) {
         use_na_ = use;
+        na_iaid_ = iaid;
     }
 
     /// @brief Place IA_PD options to request prefix assignment.
@@ -450,8 +452,10 @@ public:
     ///
     /// @param use Parameter which 'true' value indicates that client should
     /// request prefix assignment.
-    void usePD(const bool use = true) {
+    /// @param iaid IAID to be used in the IA_NA.
+    void usePD(const bool use = true, const uint32_t iaid = 5678) {
         use_pd_ = use;
+        pd_iaid_ = iaid;
     }
 
     /// @brief Simulate sending messages through a relay.
@@ -706,6 +710,11 @@ private:
 
     /// @brief FQDN requested by the client.
     Option6ClientFqdnPtr fqdn_;
+
+    /// @bref IAID used by the client when requesting address assignment.
+    uint32_t na_iaid_;
+    /// @brief IAID used by the client when requesting prefix delegation.
+    uint32_t pd_iaid_;
 };
 
 } // end of namespace isc::dhcp::test
diff --git a/src/bin/dhcp6/tests/dhcp6_srv_unittest.cc b/src/bin/dhcp6/tests/dhcp6_srv_unittest.cc
index 2013b28918..4fa269b0bc 100644
--- a/src/bin/dhcp6/tests/dhcp6_srv_unittest.cc
+++ b/src/bin/dhcp6/tests/dhcp6_srv_unittest.cc
@@ -939,23 +939,6 @@ TEST_F(Dhcpv6SrvTest, RenewSomeoneElesesLease) {
     testRenewSomeoneElsesLease(Lease::TYPE_NA, IOAddress("2001:db8::1"));
 }
 
-// This test verifies that incoming (invalid) RENEW with a prefix
-// can be handled properly.
-//
-// This test checks 3 scenarios:
-// 1. there is no such lease at all
-// 2. there is such a lease, but it is assigned to a different IAID
-// 3. there is such a lease, but it belongs to a different client
-//
-// expected:
-// - returned REPLY message has copy of client-id
-// - returned REPLY message has server-id
-// - returned REPLY message has IA_PD that includes STATUS-CODE
-// - No lease in LeaseMgr
-TEST_F(Dhcpv6SrvTest, pdRenewReject) {
-    testRenewReject(Lease::TYPE_PD, IOAddress("2001:db8:1:2::"));
-}
-
 // This test verifies that incoming (positive) RELEASE with address can be
 // handled properly, that a REPLY is generated, that the response has status
 // code and that the lease is indeed removed from the database.
diff --git a/src/bin/dhcp6/tests/dhcp6_test_utils.cc b/src/bin/dhcp6/tests/dhcp6_test_utils.cc
index 138144a560..7f716e5977 100644
--- a/src/bin/dhcp6/tests/dhcp6_test_utils.cc
+++ b/src/bin/dhcp6/tests/dhcp6_test_utils.cc
@@ -421,149 +421,6 @@ Dhcpv6SrvTest::testRenewSomeoneElsesLease(Lease::Type type, const IOAddress& add
 }
 
 void
-Dhcpv6SrvTest::testRenewReject(Lease::Type type, const IOAddress& addr) {
-
-    NakedDhcpv6Srv srv(0);
-
-    const uint32_t transid = 1234;
-    const uint32_t valid_iaid = 234;
-    const uint32_t bogus_iaid = 456;
-
-    uint32_t code;
-    uint8_t prefix_len;
-    if (type == Lease::TYPE_NA) {
-        code = D6O_IA_NA;
-        prefix_len = 128;
-    } else if (type == Lease::TYPE_PD) {
-        code = D6O_IA_PD;
-        prefix_len = pd_pool_->getLength();
-    } else {
-        isc_throw(BadValue, "Invalid lease type");
-    }
-
-    // Quick sanity check that the address we're about to use is ok
-    ASSERT_TRUE(subnet_->inPool(type, addr));
-
-    // Do not allocate leases as a result of Renew/Rebind.
-    subnet_->setAllocLeasesOnRenew(false);
-
-    // GenerateClientId() also sets duid_
-    OptionPtr clientid = generateClientId();
-
-    // Check that the lease is NOT in the database
-    Lease6Ptr l = LeaseMgrFactory::instance().getLease6(type, addr);
-    ASSERT_FALSE(l);
-
-    // Let's create a RENEW
-    Pkt6Ptr req = createMessage(DHCPV6_RENEW, type, IOAddress(addr), prefix_len,
-                                bogus_iaid);
-    req->addOption(clientid);
-    req->addOption(srv.getServerID());
-
-    // Case 1: No lease known to server
-
-    // Pass it to the server and hope for a REPLY
-    Pkt6Ptr reply = srv.processRenew(req);
-
-    // Check if we get response at all
-    checkResponse(reply, DHCPV6_REPLY, transid);
-    OptionPtr tmp = reply->getOption(code);
-    ASSERT_TRUE(tmp);
-
-    // Check that IA_?? was returned and that there's proper status code
-    boost::shared_ptr<Option6IA> ia = boost::dynamic_pointer_cast<Option6IA>(tmp);
-    ASSERT_TRUE(ia);
-
-    if (type == Lease::TYPE_PD) {
-        // For PD, the check is easy. NoBinding and no prefixes
-        checkIA_NAStatusCode(ia, STATUS_NoBinding, subnet_->getT1(), subnet_->getT2());
-    } else {
-        // For IA, it's more involved, as the server will reject the address
-        // (and send it with 0 lifetimes), but will also assign a new address.
-
-        // First, check that the requested address is rejected.
-        bool found = false;
-
-        dhcp::OptionCollection options = ia->getOptions();
-        for (isc::dhcp::OptionCollection::iterator opt = options.begin();
-             opt != options.end(); ++opt) {
-            if (opt->second->getType() != D6O_IAADDR) {
-                continue;
-            }
-
-            dhcp::Option6IAAddrPtr opt_addr =
-                boost::dynamic_pointer_cast<isc::dhcp::Option6IAAddr>(opt->second);
-            ASSERT_TRUE(opt_addr);
-
-            if (opt_addr->getAddress() != addr) {
-                // There may be other addresses, e.g. the newly assigned one
-                continue;
-            }
-
-            found = true;
-            EXPECT_NE(0, opt_addr->getPreferred());
-            EXPECT_NE(0, opt_addr->getValid());
-        }
-
-        EXPECT_TRUE(found) << "Expected address " << addr.toText()
-                           << " with zero lifetimes not found.";
-    }
-
-    // Check that there is no lease added
-    l = LeaseMgrFactory::instance().getLease6(type, addr);
-    ASSERT_FALSE(l);
-
-    // CASE 2: Lease is known and belongs to this client, but to a different IAID
-
-    // Note that preferred, valid, T1 and T2 timers and CLTT are set to invalid
-    // value on purpose. They should be updated during RENEW.
-    Lease6Ptr lease(new Lease6(type, addr, duid_, valid_iaid,
-                               501, 502, 503, 504, subnet_->getID(),
-                               HWAddrPtr(), prefix_len));
-    lease->cltt_ = 123; // Let's use it as an indicator that the lease
-                        // was NOT updated.
-    ASSERT_TRUE(LeaseMgrFactory::instance().addLease(lease));
-
-    // Pass it to the server and hope for a REPLY
-    reply = srv.processRenew(req);
-    checkResponse(reply, DHCPV6_REPLY, transid);
-    tmp = reply->getOption(code);
-    ASSERT_TRUE(tmp);
-
-    // Check that IA_?? was returned and that there's proper status code
-    ia = boost::dynamic_pointer_cast<Option6IA>(tmp);
-    ASSERT_TRUE(ia);
-    checkIA_NAStatusCode(ia, STATUS_NoBinding, subnet_->getT1(), subnet_->getT2());
-
-    // There is a iaid mis-match, so server should respond that there is
-    // no such address to renew.
-
-    // CASE 3: Lease belongs to a client with different client-id
-    req->delOption(D6O_CLIENTID);
-    ia = boost::dynamic_pointer_cast<Option6IA>(req->getOption(code));
-    ia->setIAID(valid_iaid); // Now iaid in renew matches that in leasemgr
-    req->addOption(generateClientId(13)); // generate different DUID
-                                          // (with length 13)
-
-    reply = srv.processRenew(req);
-    checkResponse(reply, DHCPV6_REPLY, transid);
-    tmp = reply->getOption(code);
-    ASSERT_TRUE(tmp);
-
-    // Check that IA_?? was returned and that there's proper status code
-    ia = boost::dynamic_pointer_cast<Option6IA>(tmp);
-    ASSERT_TRUE(ia);
-    checkIA_NAStatusCode(ia, STATUS_NoBinding, subnet_->getT1(), subnet_->getT2());
-
-    lease = LeaseMgrFactory::instance().getLease6(type, addr);
-    ASSERT_TRUE(lease);
-    // Verify that the lease was not updated.
-    EXPECT_EQ(123, lease->cltt_);
-
-    EXPECT_TRUE(LeaseMgrFactory::instance().deleteLease(addr));
-}
-
-void
 Dhcpv6SrvTest::testReleaseBasic(Lease::Type type, const IOAddress& existing,
                                 const IOAddress& release_addr) {
     NakedDhcpv6Srv srv(0);
diff --git a/src/bin/dhcp6/tests/dhcp6_test_utils.h b/src/bin/dhcp6/tests/dhcp6_test_utils.h
index d4e48319c6..6bc1334fcf 100644
--- a/src/bin/dhcp6/tests/dhcp6_test_utils.h
+++ b/src/bin/dhcp6/tests/dhcp6_test_utils.h
@@ -468,19 +468,6 @@ public:
     testRenewSomeoneElsesLease(isc::dhcp::Lease::Type type,
                                const asiolink::IOAddress& addr);
 
-    /// @brief Performs negative RENEW test
-    ///
-    /// See renewReject and pdRenewReject tests for detailed explanation.
-    /// In essence the test attempts to perform couple failed RENEW scenarios.
-    ///
-    /// This method does not throw, but uses gtest macros to signify failures.
-    ///
-    /// @param type type (TYPE_NA or TYPE_PD)
-    /// @param addr address being sent in RENEW
-    void
-    testRenewReject(isc::dhcp::Lease::Type type,
-                    const isc::asiolink::IOAddress& addr);
-
     /// @brief Performs basic (positive) RELEASE test
     ///
     /// See releaseBasic and pdReleaseBasic tests for detailed explanation.
diff --git a/src/bin/dhcp6/tests/rebind_unittest.cc b/src/bin/dhcp6/tests/rebind_unittest.cc
index d06f30c49e..2176a8b7d5 100644
--- a/src/bin/dhcp6/tests/rebind_unittest.cc
+++ b/src/bin/dhcp6/tests/rebind_unittest.cc
@@ -64,26 +64,9 @@ namespace {
 ///   - this specific configuration is used by tests which don't use relays
 ///
 /// - Configuration 6:
-///   - only addresses (no prefixes)
-///   - 1 subnet with the 2001:db8:1::/64 prefix
-///   - 'new-leases-on-renew' enabled
-///
-/// - Configuration 7:
-///   - only prefixes (no addresses)
-///   - 1 subnet with the 3000::/72
-///   - 'new-leases-on-rebew' enabled
-///
-/// - Configuration 8:
 ///   - addresses and prefixes
 ///   - address pool: 2001:db8:1::/64
 ///   - prefix pool: 3000::/72
-///   - 'new-leases-on-renew' enabled
-///
-/// - Configuration 9:
-///   - addresses and prefixes
-///   - address pool: 2001:db8:1::/64
-///   - prefix pool: 3000::/72
-///   - 'new-leases-on-renew' disabled
 ///
 const char* REBIND_CONFIGS[] = {
 // Configuration 0
@@ -93,7 +76,6 @@ const char* REBIND_CONFIGS[] = {
         "\"preferred-lifetime\": 3000,"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
         "\"subnet6\": [ { "
         "    \"pools\": [ { \"pool\": \"2001:db8:1::/64\" } ],"
         "    \"subnet\": \"2001:db8:1::/48\", "
@@ -115,7 +97,6 @@ const char* REBIND_CONFIGS[] = {
         "\"preferred-lifetime\": 3000,"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
         "\"subnet6\": [ { "
         "    \"pools\": [ { \"pool\": \"2001:db8:3::/64\" } ],"
         "    \"subnet\": \"2001:db8:3::/48\", "
@@ -137,7 +118,6 @@ const char* REBIND_CONFIGS[] = {
         "\"preferred-lifetime\": 3000,"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
         "\"subnet6\": [ { "
         "    \"pools\": [ { \"pool\": \"3000:1::/64\" } ],"
         "    \"subnet\": \"3000:1::/48\", "
@@ -159,7 +139,6 @@ const char* REBIND_CONFIGS[] = {
         "\"preferred-lifetime\": 3000,"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
         "\"subnet6\": [ { "
         "    \"pools\": [ { \"pool\": \"3000:3::/64\" } ],"
         "    \"subnet\": \"3000:3::/48\", "
@@ -181,7 +160,6 @@ const char* REBIND_CONFIGS[] = {
         "\"preferred-lifetime\": 3000,"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
         "\"subnet6\": [ { "
         "    \"pd-pools\": ["
         "        { \"prefix\": \"3000::\", "
@@ -211,7 +189,6 @@ const char* REBIND_CONFIGS[] = {
         "\"preferred-lifetime\": 3000,"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
         "\"subnet6\": [ { "
         "    \"pd-pools\": ["
         "        { \"prefix\": \"2001:db8:3:01::\", "
@@ -241,64 +218,6 @@ const char* REBIND_CONFIGS[] = {
         "\"preferred-lifetime\": 3000,"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": True,"
-        "\"subnet6\": [ { "
-        "    \"pools\": [ { \"pool\": \"2001:db8:1::/64\" } ],"
-        "    \"subnet\": \"2001:db8:1::/48\", "
-        "    \"interface-id\": \"\","
-        "    \"interface\": \"eth0\""
-        " } ],"
-        "\"valid-lifetime\": 4000 }",
-
-// Configuration 7
-    "{ \"interfaces-config\": {"
-        "  \"interfaces\": [ \"*\" ]"
-        "},"
-        "\"preferred-lifetime\": 3000,"
-        "\"rebind-timer\": 2000, "
-        "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": True,"
-        "\"subnet6\": [ { "
-        "    \"pd-pools\": ["
-        "        { \"prefix\": \"3000::\", "
-        "          \"prefix-len\": 72, "
-        "          \"delegated-len\": 80"
-        "        } ],"
-        "    \"subnet\": \"2001:db8:1::/48\", "
-        "    \"interface-id\": \"\","
-        "    \"interface\": \"eth0\""
-        " } ],"
-        "\"valid-lifetime\": 4000 }",
-
-// Configuration 8
-    "{ \"interfaces-config\": {"
-        "  \"interfaces\": [ \"*\" ]"
-        "},"
-        "\"preferred-lifetime\": 3000,"
-        "\"rebind-timer\": 2000, "
-        "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": True,"
-        "\"subnet6\": [ { "
-        "    \"pools\": [ { \"pool\": \"2001:db8:1::/64\" } ],"
-        "    \"pd-pools\": ["
-        "        { \"prefix\": \"3000::\", "
-        "          \"prefix-len\": 72, "
-        "          \"delegated-len\": 80"
-        "        } ],"
-        "    \"subnet\": \"2001:db8:1::/48\", "
-        "    \"interface-id\": \"\","
-        "    \"interface\": \"eth0\""
-        " } ],"
-        "\"valid-lifetime\": 4000 }",
-
-// Configuration 9
-    "{ \"interfaces-config\": {"
-        "  \"interfaces\": [ \"*\" ]"
-        "},"
-        "\"preferred-lifetime\": 3000,"
-        "\"rebind-timer\": 2000, "
-        "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
         "\"subnet6\": [ { "
         "    \"pools\": [ { \"pool\": \"2001:db8:1::/64\" } ],"
         "    \"pd-pools\": ["
@@ -311,8 +230,6 @@ const char* REBIND_CONFIGS[] = {
         "    \"interface\": \"eth0\""
         " } ],"
         "\"valid-lifetime\": 4000 }"
-
-
 };
 
 /// @brief Test fixture class for testing Rebind.
@@ -354,8 +271,10 @@ TEST_F(RebindTest, directClient) {
     EXPECT_TRUE(lease_server2);
 }
 
-// Test that server doesn't extend the lease when the configuration has changed
-// such that the existing subnet is replaced with a different subnet.
+// Test that server allocates a lease from a new subnet when the server
+// is reconfigured such that the previous subnet is replaced with a
+// new subnet. The client should get the new lease and an old lease
+// with zero lifetimes in the Reply.
 TEST_F(RebindTest, directClientChangingSubnet) {
     Dhcp6Client client;
     // Configure client to request IA_NA.
@@ -373,29 +292,26 @@ TEST_F(RebindTest, directClientChangingSubnet) {
 
     ASSERT_NO_THROW(client.doRebind());
 
-    // We are expecting that the server didn't extend the lease because
-    // the address that client is using doesn't match the new subnet.
-    // But, the client still has an old lease.
-    ASSERT_EQ(1, client.getLeaseNum());
-    Lease6 lease_client2 = client.getLease(0);
+    // We are expecting that the server has allocated a lease from the new
+    // subnet and sent zero lifetimes for a previous lease.
+
+    std::vector<Lease6> old_leases = client.getLeasesWithZeroLifetime();
+    ASSERT_EQ(1, old_leases.size());
+    EXPECT_EQ(lease_client.addr_, old_leases[0].addr_);
 
-    // The current lease should be exactly the same as old lease,
-    // because server shouldn't have extended.
-    EXPECT_TRUE(lease_client.addr_ == lease_client2.addr_);
-    EXPECT_EQ(0, lease_client2.preferred_lft_);
-    EXPECT_EQ(0, lease_client2.valid_lft_);
+    std::vector<Lease6> new_leases = client.getLeasesWithNonZeroLifetime();
+    ASSERT_EQ(1, new_leases.size());
 
     // Make sure, that the lease that client has, is matching the lease
     // in the lease database.
-    Lease6Ptr lease_server2 = checkLease(lease_client2);
+    Lease6Ptr lease_server2 = checkLease(new_leases[0]);
     EXPECT_TRUE(lease_server2);
-    // Client should have received NoBinding status code.
-    EXPECT_EQ(STATUS_NoBinding, client.getStatusCode(1234));
-
+    // Client should have received Success status code.
+    EXPECT_EQ(STATUS_Success, client.getStatusCode(1234));
 }
 
-// Check that the server doesn't extend the lease for the client when the
-// client sends IAID which doesn't belong to the lease that client has.
+// Check that the server allocates a new lease when the client sends IA_NA
+// with a new IAID.
 TEST_F(RebindTest, directClientChangingIAID) {
     Dhcp6Client client;
     // Configure client to request IA_NA.
@@ -406,23 +322,29 @@ TEST_F(RebindTest, directClientChangingIAID) {
     Lease6 lease_client = client.getLease(0);
     // Modify the IAID of the lease record that client stores. By adding
     // one to IAID we guarantee that the IAID will change.
-    ++client.config_.leases_[0].iaid_;
-    // Try to Rebind. Note that client will use a different IAID (which
-    // is not matching IAID that server retains for the client). Server
-    // should not find the lease that client is trying to extend and
-    // should return NoBinding.
+    client.config_.leases_[0].iaid_ = 1235;
+    client.useNA(true, 1235);
+
+    // Try to Rebind. The server should allocate new lease for this IAID.
     ASSERT_NO_THROW(client.doRebind());
-    // The lease obtained in 4-way exchange should not change after the Rebind
-    // attempt.
-    Lease6Ptr lease_server2 = checkLease(lease_client);
-    EXPECT_TRUE(lease_server2);
-    // The Status code returned to the client, should be NoBinding.
-    EXPECT_EQ(STATUS_NoBinding, client.getStatusCode(1235));
 
+    // The old lease should be returned with 0 lifetimes.
+    std::vector<Lease6> old_leases = client.getLeasesWithZeroLifetime();
+    ASSERT_EQ(1, old_leases.size());
+    EXPECT_EQ(lease_client.addr_, old_leases[0].addr_);
+
+    // The new lease should be allocated.
+    std::vector<Lease6> new_leases = client.getLeasesWithNonZeroLifetime();
+    ASSERT_EQ(1, new_leases.size());
+
+    Lease6Ptr lease_server2 = checkLease(new_leases[0]);
+    EXPECT_TRUE(lease_server2);
+    // The Status code returned to the client, should be Success.
+    EXPECT_EQ(STATUS_Success, client.getStatusCode(1235));
 }
 
-// Check that server sends NoBinding when the lease has been lost from
-// the database and client is trying to Rebind it.
+// Check that the server allocates a requested lease for the client when
+// this lease has been lost from the database.
 TEST_F(RebindTest, directClientLostLease) {
     Dhcp6Client client;
     // Configure client to request IA_NA.
@@ -434,11 +356,15 @@ TEST_F(RebindTest, directClientLostLease) {
     // The lease has been acquired. Now, let's explicitly remove it from the
     // lease database.
     LeaseMgrFactory::instance().deleteLease(lease_client.addr_);
-    // An attempt to Rebind should fail. The lease should not be found by
-    // the server and the server should return NoBinding status code.
+    // Send Rebind.
     ASSERT_NO_THROW(client.doRebind());
-    ASSERT_EQ(1, client.getLeaseNum());
-    EXPECT_EQ(STATUS_NoBinding, client.getStatusCode(1234));
+
+    // The server should re-allocate this lease to the client.
+    std::vector<Lease6> new_leases = client.getLeasesWithNonZeroLifetime();
+    ASSERT_EQ(1, new_leases.size());
+    EXPECT_EQ(lease_client.addr_, new_leases[0].addr_);
+    // Status code should be Success.
+    EXPECT_EQ(STATUS_Success, client.getStatusCode(1234));
 }
 
 /// @todo Extend tests for direct client changing address.
@@ -520,25 +446,32 @@ TEST_F(RebindTest, relayedClientChangingIAID) {
     ASSERT_NO_FATAL_FAILURE(requestLease(REBIND_CONFIGS[2], 2, client));
     // Keep the client's lease for future reference.
     Lease6 lease_client = client.getLease(0);
+
     // Modify the IAID of the lease record that client stores. By adding
     // one to IAID we guarantee that the IAID will change.
-    ++client.config_.leases_[0].iaid_;
-    // Try to Rebind. Note that client will use a different IAID (which
-    // is not matching IAID that server retains for the client). Server
-    // should not find the lease that client is trying to extend and
-    // should return NoBinding.
+    client.config_.leases_[0].iaid_ = 1235;
+    client.useNA(true, 1235);
+
+    // Try to Rebind. The server should allocate new lease for this IAID.
     ASSERT_NO_THROW(client.doRebind());
-    // The lease obtained in 4-way exchange should not change after the Rebind
-    // attempt.
-    Lease6Ptr lease_server2 = checkLease(lease_client);
-    EXPECT_TRUE(lease_server2);
-    // The Status code returned to the client, should be NoBinding.
-    EXPECT_EQ(STATUS_NoBinding, client.getStatusCode(1235));
 
+    // The old lease should be returned with 0 lifetimes.
+    std::vector<Lease6> old_leases = client.getLeasesWithZeroLifetime();
+    ASSERT_EQ(1, old_leases.size());
+    EXPECT_EQ(lease_client.addr_, old_leases[0].addr_);
+
+    // The new lease should be allocated.
+    std::vector<Lease6> new_leases = client.getLeasesWithNonZeroLifetime();
+    ASSERT_EQ(1, new_leases.size());
+
+    Lease6Ptr lease_server2 = checkLease(new_leases[0]);
+    EXPECT_TRUE(lease_server2);
+    // The Status code returned to the client, should be Success.
+    EXPECT_EQ(STATUS_Success, client.getStatusCode(1235));
 }
 
-// Check that the relayed client receives NoBinding when the lease that he
-// is Rebinding has been lost from the database.
+// Check that the server allocates a requested lease for the client when
+// this lease has been lost from the database.
 TEST_F(RebindTest, relayedClientLostLease) {
     Dhcp6Client client;
     // Configure client to request IA_NA.
@@ -554,11 +487,16 @@ TEST_F(RebindTest, relayedClientLostLease) {
     // The lease has been acquired. Now, let's explicitly remove it from the
     // lease database.
     LeaseMgrFactory::instance().deleteLease(lease_client.addr_);
-    // An attempt to Rebind should fail. The lease should not be found by
-    // the server and the server should return NoBinding status code.
+
+    // Send Rebind.
     ASSERT_NO_THROW(client.doRebind());
-    ASSERT_EQ(1, client.getLeaseNum());
-    EXPECT_EQ(STATUS_NoBinding, client.getStatusCode(1234));
+
+    // The server should re-allocate this lease to the client.
+    std::vector<Lease6> new_leases = client.getLeasesWithNonZeroLifetime();
+    ASSERT_EQ(1, new_leases.size());
+    EXPECT_EQ(lease_client.addr_, new_leases[0].addr_);
+    // Status code should be Success.
+    EXPECT_EQ(STATUS_Success, client.getStatusCode(1234));
 }
 
 // Check that relayed client receives the IA with lifetimes of 0, when
@@ -642,9 +580,10 @@ TEST_F(RebindTest, directClientPD) {
     EXPECT_TRUE(lease_server2);
 }
 
-// Check that the prefix lifetime is not extended for the client in case
-// the configuration has been changed such, that the subnet he is using
-// doesn't exist anymore.
+// Test that server allocates a lease from a new subnet when the server
+// is reconfigured such that the previous subnet is replaced with a
+// new subnet. The client should get the new lease and an old lease
+// with zero lifetimes in the Reply.
 TEST_F(RebindTest, directClientPDChangingSubnet) {
     Dhcp6Client client;
     // Configure client to request IA_PD.
@@ -657,31 +596,31 @@ TEST_F(RebindTest, directClientPDChangingSubnet) {
     // client's interface. Note that there will also be a new subnet
     // id assigned to the subnet on this interface.
     configure(REBIND_CONFIGS[5], *client.getServer());
-    // Try to rebind, using the address that the client had acquired using
+
+    // Try to rebind, using the prefix that the client had acquired using
     // previous server configuration.
-    ASSERT_NO_THROW(client.doRebind());
-    // Make sure that the server has discarded client's message. In such case,
-    // the message sent back to the client should be NULL.
-    EXPECT_FALSE(client.getContext().response_)
-        << "The server responded to the Rebind message, while it should have"
-        " discarded it because there is no binding for the client.";
-    // We are expecting that the server didn't extend the lease because
-    // the address that client is using doesn't match the new subnet.
-    // But, the client still has an old lease.
-    ASSERT_EQ(1, client.getLeaseNum());
-    Lease6 lease_client2 = client.getLease(0);
-    // The current lease should be exactly the same as old lease,
-    // because server shouldn't have extended.
-    EXPECT_TRUE(lease_client == lease_client2);
+    client.doRebind();
+
+    // We are expecting that the server has allocated a lease from the new
+    // subnet and sent zero lifetimes for a previous lease.
+
+    std::vector<Lease6> old_leases = client.getLeasesWithZeroLifetime();
+    ASSERT_EQ(1, old_leases.size());
+    EXPECT_EQ(lease_client.addr_, old_leases[0].addr_);
+
+    std::vector<Lease6> new_leases = client.getLeasesWithNonZeroLifetime();
+    ASSERT_EQ(1, new_leases.size());
+
     // Make sure, that the lease that client has, is matching the lease
     // in the lease database.
-    Lease6Ptr lease_server2 = checkLease(lease_client2);
+    Lease6Ptr lease_server2 = checkLease(new_leases[0]);
     EXPECT_TRUE(lease_server2);
+    // Client should have received Success status code.
+    EXPECT_EQ(STATUS_Success, client.getStatusCode(5678));
 }
 
-// Check that the prefix lifetime is not extended for the client when the
-// IAID used in the Rebind is not matching the one recorded by the server
-// for the particular client.
+// Check that the server allocates a new lease when the client sends IA_PD
+// with a new IAID.
 TEST_F(RebindTest, directClientPDChangingIAID) {
     Dhcp6Client client;
     // Configure client to request IA_PD.
@@ -690,24 +629,28 @@ TEST_F(RebindTest, directClientPDChangingIAID) {
     ASSERT_NO_FATAL_FAILURE(requestLease(REBIND_CONFIGS[4], 2, client));
     // Keep the client's lease for future reference.
     Lease6 lease_client = client.getLease(0);
+
     // Modify the IAID of the lease record that client stores. By adding
     // one to IAID we guarantee that the IAID will change.
-    ++client.config_.leases_[0].iaid_;
-    // Try to Rebind. Note that client will use a different IAID (which
-    // is not matching IAID that server retains for the client). This is
-    // a condition described in RFC3633, section 12.2 as the server finds
-    // no binding for the client. It is an indication that some other
-    // server has probably allocated the lease for the client. Hence, our
-    // server should discard the message.
+    client.config_.leases_[0].iaid_ = 5679;
+    client.usePD(true, 5679);
+
+    // Try to Rebind. The server should allocate new lease for this IAID.
     ASSERT_NO_THROW(client.doRebind());
-    // Make sure that the server has discarded client's message. In such case,
-    // the message sent back to the client should be NULL.
-    EXPECT_FALSE(client.getContext().response_)
-        << "The server responded to the Rebind message, while it should have"
-        " discarded it because there is no binding for the client.";
-    // Check that server still has the same lease.
-    Lease6Ptr lease_server = checkLease(lease_client);
-    EXPECT_TRUE(lease_server);
+
+    // The old lease should be returned with 0 lifetimes.
+    std::vector<Lease6> old_leases = client.getLeasesWithZeroLifetime();
+    ASSERT_EQ(1, old_leases.size());
+    EXPECT_EQ(lease_client.addr_, old_leases[0].addr_);
+
+    // The new lease should be allocated.
+    std::vector<Lease6> new_leases = client.getLeasesWithNonZeroLifetime();
+    ASSERT_EQ(1, new_leases.size());
+
+    Lease6Ptr lease_server2 = checkLease(new_leases[0]);
+    EXPECT_TRUE(lease_server2);
+    // The Status code returned to the client, should be Success.
+    EXPECT_EQ(STATUS_Success, client.getStatusCode(5679));
 }
 
 // Check that the prefix lifetime is not extended for the client when the
@@ -839,7 +782,7 @@ TEST_F(RebindTest, requestPrefixInRebind) {
     client.usePD();
 
     // Configure the server with NA pools only.
-    ASSERT_NO_THROW(configure(REBIND_CONFIGS[6], *client.getServer()));
+    ASSERT_NO_THROW(configure(REBIND_CONFIGS[0], *client.getServer()));
 
     // Perform 4-way exchange.
     ASSERT_NO_THROW(client.doSARR());
@@ -864,7 +807,7 @@ TEST_F(RebindTest, requestPrefixInRebind) {
     ASSERT_EQ(STATUS_NoPrefixAvail, client.getStatusCode(5678));
 
     // Reconfigure the server to use both NA and PD pools.
-    configure(REBIND_CONFIGS[8], *client.getServer());
+    configure(REBIND_CONFIGS[6], *client.getServer());
 
     // Send Rebind message to the server, including IA_NA and requesting IA_PD.
     ASSERT_NO_THROW(client.doRebind());
@@ -894,7 +837,7 @@ TEST_F(RebindTest, requestAddressInRebind) {
     client.usePD();
 
     // Configure the server with PD pools only.
-    ASSERT_NO_THROW(configure(REBIND_CONFIGS[7], *client.getServer()));
+    ASSERT_NO_THROW(configure(REBIND_CONFIGS[4], *client.getServer()));
 
     // Perform 4-way exchange.
     ASSERT_NO_THROW(client.doSARR());
@@ -921,7 +864,7 @@ TEST_F(RebindTest, requestAddressInRebind) {
     ASSERT_EQ(STATUS_NoAddrsAvail, client.getStatusCode(1234));
 
     // Reconfigure the server to use both NA and PD pools.
-    configure(REBIND_CONFIGS[8], *client.getServer());
+    configure(REBIND_CONFIGS[6], *client.getServer());
 
     // Send Rebind message to the server, including IA_PD and requesting IA_NA.
     ASSERT_NO_THROW(client.doRebind());
@@ -939,102 +882,5 @@ TEST_F(RebindTest, requestAddressInRebind) {
     EXPECT_EQ(STATUS_Success, client.getStatusCode(1234));
 }
 
-// This test verifies that when the client requests the prefix delegation
-// while it is renewing an address lease its message is dropped.
-TEST_F(RebindTest, requestPrefixInRebindNotAllowed) {
-    Dhcp6Client client;
-
-    // Configure client to request IA_NA and IA_PD.
-    client.useNA();
-    client.usePD();
-
-    // Configure the server with NA pools only.
-    ASSERT_NO_THROW(configure(REBIND_CONFIGS[0], *client.getServer()));
-
-    // Perform 4-way exchange.
-    ASSERT_NO_THROW(client.doSARR());
-
-    // Simulate aging of leases.
-    client.fastFwdTime(1000);
-
-    // Make sure that the client has acquired NA lease.
-    std::vector<Lease6> leases_client_na = client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(1, leases_client_na.size());
-
-    // The client should not acquire a PD lease.
-    std::vector<Lease6> leases_client_pd = client.getLeasesByType(Lease::TYPE_PD);
-    ASSERT_TRUE(leases_client_pd.empty());
-    ASSERT_EQ(STATUS_NoPrefixAvail, client.getStatusCode(5678));
-
-    // Send Rebind message to the server, including IA_NA and requesting IA_PD.
-    ASSERT_NO_THROW(client.doRebind());
-    EXPECT_FALSE(client.getContext().response_);
-
-    // Reconfigure the server to use both NA and PD pools.
-    configure(REBIND_CONFIGS[9], *client.getServer());
-
-    // Send Rebind message to the server, including IA_NA and requesting IA_PD.
-    ASSERT_NO_THROW(client.doRebind());
-    EXPECT_FALSE(client.getContext().response_);
-}
-
-// This test verifies that when the client requests an address assignment
-// while it is renewing a prefix lease it is returned NoBinding, when
-// the server is not configured to allocate new leases during Renew.
-TEST_F(RebindTest, requestAddressInRebindNotAllowed) {
-    Dhcp6Client client;
-
-    // Configure client to request IA_NA and IA_PD.
-    client.useNA();
-    client.usePD();
-
-    // Configure the server with PD pools only.
-    ASSERT_NO_THROW(configure(REBIND_CONFIGS[4], *client.getServer()));
-
-    // Perform 4-way exchange.
-    ASSERT_NO_THROW(client.doSARR());
-
-    // Simulate aging of leases.
-    client.fastFwdTime(1000);
-
-    // Make sure that the client has acquired PD lease.
-    std::vector<Lease6> leases_client_pd = client.getLeasesByType(Lease::TYPE_PD);
-    ASSERT_EQ(1, leases_client_pd.size());
-    EXPECT_EQ(STATUS_Success, client.getStatusCode(5678));
-
-    // The client should not acquire a NA lease.
-    std::vector<Lease6> leases_client_na =
-        client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(0, leases_client_na.size());
-    ASSERT_EQ(STATUS_NoAddrsAvail, client.getStatusCode(1234));
-
-    // Send Rebind message to the server, including IA_PD and requesting IA_NA.
-    // The server should return NoBinding status code in this case.
-    ASSERT_NO_THROW(client.doRebind());
-    leases_client_na = client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(0, leases_client_na.size());
-    ASSERT_EQ(STATUS_NoBinding, client.getStatusCode(1234));
-
-    // Reconfigure the server to use both NA and PD pools.
-    configure(REBIND_CONFIGS[9], *client.getServer());
-
-    // Send Rebind message to the server, including IA_PD and requesting IA_NA.
-    ASSERT_NO_THROW(client.doRebind());
-
-    // Make sure that the client has renewed PD lease.
-    std::vector<Lease6> leases_client_pd_renewed =
-        client.getLeasesByType(Lease::TYPE_PD);
-    ASSERT_EQ(1, leases_client_pd_renewed.size());
-    EXPECT_EQ(STATUS_Success, client.getStatusCode(5678));
-    EXPECT_GE(leases_client_pd_renewed[0].cltt_ - leases_client_pd[0].cltt_, 1000);
-
-    // The server should not allocate an address to the client, as this has been
-    // explicitly disabled in the configuration. Instead, it should send
-    // NoBinding status code.
-    leases_client_na = client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(0, leases_client_na.size());
-    EXPECT_EQ(STATUS_NoBinding, client.getStatusCode(1234));
-}
-
 
 } // end of anonymous namespace
diff --git a/src/bin/dhcp6/tests/renew_unittest.cc b/src/bin/dhcp6/tests/renew_unittest.cc
index 497a355472..cef2b7ef2c 100644
--- a/src/bin/dhcp6/tests/renew_unittest.cc
+++ b/src/bin/dhcp6/tests/renew_unittest.cc
@@ -44,23 +44,6 @@ namespace {
 ///   - address pool: 2001:db8:1::/64
 ///   - prefix pool: 3000::/72
 ///
-/// - Configuration 3:
-///   - only addresses (no prefixes)
-///   - 1 subnet with 2001:db8:1::/64 pool
-///   - 'new-leases-on-renew' disabled
-///
-/// - Configuration 4:
-///   - only prefixes (no addresses)
-///   - prefix pool: 3000::/72
-///   - 'new-leases-on-renew' disabled
-///
-/// - Configuration 5:
-///   - addresses and prefixes
-///   - 1 subnet with one address pool and one prefix pool
-///   - address pool: 2001:db8:1::/64
-///   - prefix pool: 3000::/72
-///   - 'new-leases-on-renew' disabled
-///
 const char* RENEW_CONFIGS[] = {
 // Configuration 0
     "{ \"interfaces-config\": {"
@@ -114,63 +97,6 @@ const char* RENEW_CONFIGS[] = {
         "    \"interface-id\": \"\","
         "    \"interface\": \"eth0\""
         " } ],"
-        "\"valid-lifetime\": 4000 }",
-
-// Configuration 3
-    "{ \"interfaces-config\": {"
-        "  \"interfaces\": [ \"*\" ]"
-        "},"
-        "\"preferred-lifetime\": 3000,"
-        "\"rebind-timer\": 2000, "
-        "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
-        "\"subnet6\": [ { "
-        "    \"pools\": [ { \"pool\": \"2001:db8:1::/64\" } ],"
-        "    \"subnet\": \"2001:db8:1::/48\", "
-        "    \"interface-id\": \"\","
-        "    \"interface\": \"eth0\""
-        " } ],"
-        "\"valid-lifetime\": 4000 }",
-
-// Configuration 4
-    "{ \"interfaces-config\": {"
-        "  \"interfaces\": [ \"*\" ]"
-        "},"
-        "\"preferred-lifetime\": 3000,"
-        "\"rebind-timer\": 2000, "
-        "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
-        "\"subnet6\": [ { "
-        "    \"pd-pools\": ["
-        "        { \"prefix\": \"3000::\", "
-        "          \"prefix-len\": 72, "
-        "          \"delegated-len\": 80"
-        "        } ],"
-        "    \"subnet\": \"2001:db8:1::/48\", "
-        "    \"interface-id\": \"\","
-        "    \"interface\": \"eth0\""
-        " } ],"
-        "\"valid-lifetime\": 4000 }",
-
-// Configuration 5
-    "{ \"interfaces-config\": {"
-        "  \"interfaces\": [ \"*\" ]"
-        "},"
-        "\"preferred-lifetime\": 3000,"
-        "\"rebind-timer\": 2000, "
-        "\"renew-timer\": 1000, "
-        "\"new-leases-on-renew\": False,"
-        "\"subnet6\": [ { "
-        "    \"pools\": [ { \"pool\": \"2001:db8:1::/64\" } ],"
-        "    \"pd-pools\": ["
-        "        { \"prefix\": \"3000::\", "
-        "          \"prefix-len\": 72, "
-        "          \"delegated-len\": 80"
-        "        } ],"
-        "    \"subnet\": \"2001:db8:1::/48\", "
-        "    \"interface-id\": \"\","
-        "    \"interface\": \"eth0\""
-        " } ],"
         "\"valid-lifetime\": 4000 }"
 };
 
@@ -427,120 +353,5 @@ TEST_F(RenewTest, requestAddressInRenewHint) {
     EXPECT_EQ(STATUS_Success, client.getStatusCode(1234));
 }
 
-// This test verifies that when the client requests the prefix delegation
-// while it is renewing an address lease it is returned NoBinding, when
-// the server is not configured to allocate new leases during Renew.
-TEST_F(RenewTest, requestPrefixInRenewNotAllowed) {
-    Dhcp6Client client;
-
-    // Configure client to request IA_NA and IA_PD.
-    client.useNA();
-    client.usePD();
-
-    // Configure the server with NA pools only.
-    ASSERT_NO_THROW(configure(RENEW_CONFIGS[3], *client.getServer()));
-
-    // Perform 4-way exchange.
-    ASSERT_NO_THROW(client.doSARR());
-
-    // Simulate aging of leases.
-    client.fastFwdTime(1000);
-
-    // Make sure that the client has acquired NA lease.
-    std::vector<Lease6> leases_client_na = client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(1, leases_client_na.size());
-
-    // The client should not acquire a PD lease.
-    std::vector<Lease6> leases_client_pd = client.getLeasesByType(Lease::TYPE_PD);
-    ASSERT_TRUE(leases_client_pd.empty());
-    ASSERT_EQ(STATUS_NoPrefixAvail, client.getStatusCode(5678));
-
-    // Send Renew message to the server, including IA_NA and requesting IA_PD.
-    ASSERT_NO_THROW(client.doRenew());
-    leases_client_pd = client.getLeasesByType(Lease::TYPE_PD);
-    ASSERT_TRUE(leases_client_pd.empty());
-    ASSERT_EQ(STATUS_NoBinding, client.getStatusCode(5678));
-
-    // Reconfigure the server to use both NA and PD pools.
-    configure(RENEW_CONFIGS[5], *client.getServer());
-
-    // Send Renew message to the server, including IA_NA and requesting IA_PD.
-    ASSERT_NO_THROW(client.doRenew());
-
-    // Make sure that the client has acquired NA lease.
-    std::vector<Lease6> leases_client_na_renewed =
-        client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(1, leases_client_na_renewed.size());
-    EXPECT_EQ(STATUS_Success, client.getStatusCode(1234));
-
-    // The lease should have been renewed.
-    EXPECT_EQ(1000, leases_client_na_renewed[0].cltt_ - leases_client_na[0].cltt_);
-
-    // The server should not delegate a prefix to the client, as this has been
-    // explicitly disabled in the configuration. Instead, it should send
-    // NoBinding status code.
-    leases_client_pd = client.getLeasesByType(Lease::TYPE_PD);
-    ASSERT_EQ(0, leases_client_pd.size());
-    EXPECT_EQ(STATUS_NoBinding, client.getStatusCode(5678));
-}
-
-// This test verifies that when the client requests an address assignment
-// while it is renewing a prefix lease it is returned NoBinding, when
-// the server is not configured to allocate new leases during Renew.
-TEST_F(RenewTest, requestAddressInRenewNotAllowed) {
-    Dhcp6Client client;
-
-    // Configure client to request IA_NA and IA_PD.
-    client.useNA();
-    client.usePD();
-
-    // Configure the server with PD pools only.
-    ASSERT_NO_THROW(configure(RENEW_CONFIGS[4], *client.getServer()));
-
-    // Perform 4-way exchange.
-    ASSERT_NO_THROW(client.doSARR());
-
-    // Simulate aging of leases.
-    client.fastFwdTime(1000);
-
-    // Make sure that the client has acquired PD lease.
-    std::vector<Lease6> leases_client_pd = client.getLeasesByType(Lease::TYPE_PD);
-    ASSERT_EQ(1, leases_client_pd.size());
-    EXPECT_EQ(STATUS_Success, client.getStatusCode(5678));
-
-    // The client should not acquire a NA lease.
-    std::vector<Lease6> leases_client_na =
-        client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(0, leases_client_na.size());
-    ASSERT_EQ(STATUS_NoAddrsAvail, client.getStatusCode(1234));
-
-    // Send Renew message to the server, including IA_PD and requesting IA_NA.
-    // The server should return NoBinding status code in this case.
-    ASSERT_NO_THROW(client.doRenew());
-    leases_client_na = client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(0, leases_client_na.size());
-    ASSERT_EQ(STATUS_NoBinding, client.getStatusCode(1234));
-
-    // Reconfigure the server to use both NA and PD pools.
-    configure(RENEW_CONFIGS[5], *client.getServer());
-
-    // Send Renew message to the server, including IA_PD and requesting IA_NA.
-    ASSERT_NO_THROW(client.doRenew());
-
-    // Make sure that the client has renewed PD lease.
-    std::vector<Lease6> leases_client_pd_renewed =
-        client.getLeasesByType(Lease::TYPE_PD);
-    ASSERT_EQ(1, leases_client_pd_renewed.size());
-    EXPECT_EQ(STATUS_Success, client.getStatusCode(5678));
-    EXPECT_GE(leases_client_pd_renewed[0].cltt_ - leases_client_pd[0].cltt_, 1000);
-
-    // The server should not allocate an address to the client, as this has been
-    // explicitly disabled in the configuration. Instead, it should send
-    // NoBinding status code.
-    leases_client_na = client.getLeasesByType(Lease::TYPE_NA);
-    ASSERT_EQ(0, leases_client_na.size());
-    EXPECT_EQ(STATUS_NoBinding, client.getStatusCode(1234));
-}
-
 
 } // end of anonymous namespace
diff --git a/src/lib/dhcpsrv/alloc_engine.cc b/src/lib/dhcpsrv/alloc_engine.cc
index f3e0a742b7..0ccef1e2dc 100644
--- a/src/lib/dhcpsrv/alloc_engine.cc
+++ b/src/lib/dhcpsrv/alloc_engine.cc
@@ -297,7 +297,7 @@ AllocEngine::ClientContext6::ClientContext6()
     : subnet_(), duid_(), iaid_(0), type_(Lease::TYPE_NA), hwaddr_(),
       hints_(), fwd_dns_update_(false), rev_dns_update_(false), hostname_(""),
       callout_handle_(), fake_allocation_(false), old_leases_(), host_(),
-      query_(), ia_rsp_(), allow_new_leases_in_renewals_(false) {
+      query_(), ia_rsp_() {
 }
 
 AllocEngine::ClientContext6::ClientContext6(const Subnet6Ptr& subnet, const DuidPtr& duid,
@@ -310,8 +310,7 @@ AllocEngine::ClientContext6::ClientContext6(const Subnet6Ptr& subnet, const Duid
     subnet_(subnet), duid_(duid), iaid_(iaid), type_(type), hwaddr_(),
     hints_(), fwd_dns_update_(fwd_dns), rev_dns_update_(rev_dns),
     hostname_(hostname), fake_allocation_(fake_allocation),
-    old_leases_(), host_(), query_(), ia_rsp_(),
-    allow_new_leases_in_renewals_(false) {
+    old_leases_(), host_(), query_(), ia_rsp_() {
 
     static asiolink::IOAddress any("::");
 
@@ -1093,18 +1092,6 @@ AllocEngine::renewLeases6(ClientContext6& ctx) {
         Lease6Collection leases = LeaseMgrFactory::instance()
             .getLeases6(ctx.type_, *ctx.duid_, ctx.iaid_, ctx.subnet_->getID());
 
-        // If this client has no leases and we do not allow allocation of
-        // new leases in renewals, return now to indicate NoBinding.
-        if (leases.empty() && !ctx.allow_new_leases_in_renewals_) {
-            LOG_DEBUG(alloc_engine_logger, ALLOC_ENGINE_DBG_TRACE,
-                      ALLOC_ENGINE_V6_NO_BINDING)
-                .arg(ctx.query_->getLabel())
-                .arg(Lease::typeToText(ctx.type_))
-                .arg(ctx.iaid_)
-                .arg(ctx.subnet_->getID());
-            return (Lease6Collection());
-        }
-
         if (!leases.empty()) {
             LOG_DEBUG(alloc_engine_logger, ALLOC_ENGINE_DBG_TRACE,
                       ALLOC_ENGINE_V6_RENEW_REMOVE_RESERVED)
@@ -1135,7 +1122,7 @@ AllocEngine::renewLeases6(ClientContext6& ctx) {
         // Depending on the configuration, we may enable or disable granting
         // new leases during renewals. This is controlled with the
         // allow_new_leases_in_renewals_ field.
-        if (leases.empty() && ctx.allow_new_leases_in_renewals_) {
+        if (leases.empty()) {
 
             LOG_DEBUG(alloc_engine_logger, ALLOC_ENGINE_DBG_TRACE,
                       ALLOC_ENGINE_V6_EXTEND_ALLOC_UNRESERVED)
diff --git a/src/lib/dhcpsrv/alloc_engine.h b/src/lib/dhcpsrv/alloc_engine.h
index 408e4dc91e..487312fa1d 100644
--- a/src/lib/dhcpsrv/alloc_engine.h
+++ b/src/lib/dhcpsrv/alloc_engine.h
@@ -357,18 +357,6 @@ public:
         /// @brief A pointer to the IA_NA/IA_PD option to be sent in response
         Option6IAPtr ia_rsp_;
 
-
-        /// @brief Specifies whether new leases in Renew/Rebind are allowed
-        ///
-        /// This field controls what to do when renewing or rebinding client
-        /// does not have any leases. RFC3315 and the stateful-issues draft do
-        /// not specify it and it is left up to the server configuration policy.
-        /// False (the default) means that the client will not get any new
-        /// unreserved leases if his existing leases are no longer suitable.
-        /// True means that the allocation engine will do its best to assign
-        /// something.
-        bool allow_new_leases_in_renewals_;
-
         /// @brief Default constructor.
         ClientContext6();
 
diff --git a/src/lib/dhcpsrv/alloc_engine_messages.mes b/src/lib/dhcpsrv/alloc_engine_messages.mes
index 60893718bc..8488c9f69a 100644
--- a/src/lib/dhcpsrv/alloc_engine_messages.mes
+++ b/src/lib/dhcpsrv/alloc_engine_messages.mes
@@ -246,15 +246,6 @@ reserved for it.
 This informational message signals that the specified client was assigned the prefix
 reserved for it.
 
-% ALLOC_ENGINE_V6_NO_BINDING %1: client requesting renew/rebind has no binding for lease type %2, IAID %3 and subnet id %4
-This debug message is issued when the allocation engine determines that the renewing
-client has no binding for the given lease type, IAID and subnet id. The server is
-configured to not allocate new bindings during the Renew/Rebind. Hence the
-server doesn't allocate new leases and returns NoBinding status code or
-ignores the message. The first argument contains the client and the
-transaction identification information. The remaining arguments hold
-the lease type, IAID and subnet id respectively.
-
 % ALLOC_ENGINE_V6_RENEW_HR allocating leases reserved for the client %1 as a result of Renew
 This debug message is issued when the allocation engine tries to
 allocate reserved leases for the client sending a Renew message.
diff --git a/src/lib/dhcpsrv/tests/alloc_engine_utils.cc b/src/lib/dhcpsrv/tests/alloc_engine_utils.cc
index d5894d92cc..53227c773d 100644
--- a/src/lib/dhcpsrv/tests/alloc_engine_utils.cc
+++ b/src/lib/dhcpsrv/tests/alloc_engine_utils.cc
@@ -233,7 +233,6 @@ AllocEngine6Test::simpleAlloc6Test(const Pool6Ptr& pool, const IOAddress& hint,
 Lease6Collection
 AllocEngine6Test::renewTest(AllocEngine& engine, const Pool6Ptr& pool,
                             AllocEngine::HintContainer& hints,
-                            bool allow_new_leases_in_renewal,
                             bool in_pool) {
 
     Lease::Type type = pool->getType();
@@ -243,7 +242,6 @@ AllocEngine6Test::renewTest(AllocEngine& engine, const Pool6Ptr& pool,
                                     type, false, false, "", false);
     ctx.hints_ = hints;
     ctx.query_.reset(new Pkt6(DHCPV6_RENEW, 123));
-    ctx.allow_new_leases_in_renewals_ = allow_new_leases_in_renewal;
     ctx.query_.reset(new Pkt6(DHCPV6_RENEW, 1234));
 
     findReservation(engine, ctx);
diff --git a/src/lib/dhcpsrv/tests/alloc_engine_utils.h b/src/lib/dhcpsrv/tests/alloc_engine_utils.h
index bc0728aa57..128c5060d7 100644
--- a/src/lib/dhcpsrv/tests/alloc_engine_utils.h
+++ b/src/lib/dhcpsrv/tests/alloc_engine_utils.h
@@ -246,13 +246,10 @@ public:
     /// @param engine a reference to Allocation Engine
     /// @param pool pool from which the lease will be allocated from
     /// @param hints address to be used as a hint
-    /// @param allow_new_leases_in_renewal - specifies how to set the
-    ///        allow_new_leases_in_renewal flag in ClientContext6
     /// @param in_pool specifies whether the lease is expected to be in pool
     /// @return allocated lease(s) (may be empty)
     Lease6Collection renewTest(AllocEngine& engine, const Pool6Ptr& pool,
                                AllocEngine::HintContainer& hints,
-                               bool allow_new_leases_in_renewal,
                                bool in_pool = true);
 
     /// @brief Checks if the address allocation with a hint that is in range,