コード例 #1
0
        public void DynDnsHandler_Udp_ADDRESSLIST()
        {
            // Start a Dynamic DNS service handler and a client, register two ADDRESSLIST
            // records for TEST1.COM and confirm that A queries return both entries.
            // I'm also going to add an ADDRESS record for TEST2.COM and verify that this address
            // is never returned.

            DynDnsClientSettings clientSettings;
            DynDnsHandler        handler = null;
            DynDnsClient         client  = null;
            DnsResponse          response;

            try
            {
                handler = new DynDnsHandler();
                handler.Start(router, null, null, null);

                clientSettings = new DynDnsClientSettings()
                {
                    Mode                = DynDnsMode.Udp,
                    NameServers         = new NetworkBinding[] { new NetworkBinding("127.0.0.1:DYNAMIC-DNS") },
                    UdpRegisterInterval = TimeSpan.FromSeconds(1)
                };

                client = new DynDnsClient();
                client.Register(new DynDnsHostEntry("test1.com,10.0.0.1,1000,ADDRESSLIST"));
                client.Register(new DynDnsHostEntry("test1.com,10.0.0.2,1000,ADDRESSLIST"));
                client.Register(new DynDnsHostEntry("test2.com,10.0.0.3,1000,ADDRESSLIST"));
                client.Open(router, clientSettings);

                // Wait for everything to spin up.

                Thread.Sleep(3000);

                // Perform an A query and verify that we get both addresses in response.

                response = DnsResolver.Query(IPAddress.Loopback, new DnsRequest(DnsFlag.NONE, "test1.com.", DnsQType.A), TimeSpan.FromSeconds(2));

                Assert.AreEqual("test1.com.", response.QName);
                Assert.AreEqual(DnsQType.A, response.QType);
                Assert.AreEqual(2, response.Answers.Count);

                Assert.IsNotNull(response.Answers.SingleOrDefault(r => ((A_RR)r).Address.Equals(IPAddress.Parse("10.0.0.1"))));
                Assert.IsNotNull(response.Answers.SingleOrDefault(r => ((A_RR)r).Address.Equals(IPAddress.Parse("10.0.0.2"))));
            }
            finally
            {
                if (client != null)
                {
                    client.Close();
                }

                if (handler != null)
                {
                    handler.Stop();
                }
            }
        }
コード例 #2
0
        public void DynDnsHandler_Cluster_ADDRESSLIST()
        {
            // Start a Dynamic DNS service handler and a client, register two ADDRESSLIST
            // records for TEST1.COM and confirm that A queries return both entries.
            // I'm also going to add an ADDRESS record for TEST2.COM and verify that this address
            // is never returned.

            DynDnsHandler handler = null;
            DynDnsClient  client  = null;
            DnsResponse   response;

            try
            {
                handler = new DynDnsHandler();
                handler.Start(router, null, null, null);

                client = new DynDnsClient();
                client.Register(new DynDnsHostEntry("test1.com,10.0.0.1,1000,ADDRESSLIST"));
                client.Register(new DynDnsHostEntry("test1.com,10.0.0.2,1000,ADDRESSLIST"));
                client.Register(new DynDnsHostEntry("test2.com,10.0.0.3,1000,ADDRESSLIST"));
                client.Open(router, new DynDnsClientSettings("DynDnsClient"));

                // Wait for all cluster members to come online and for
                // the host registrations to be replicated.

                WaitForOnline(handler.Cluster, waitTime);
                WaitForOnline(client.Cluster, waitTime);
                Thread.Sleep(2000);

                // Perform an A query and verify that we get both addresses in response.

                response = DnsResolver.Query(IPAddress.Loopback, new DnsRequest(DnsFlag.NONE, "test1.com.", DnsQType.A), TimeSpan.FromSeconds(2));

                Assert.AreEqual("test1.com.", response.QName);
                Assert.AreEqual(DnsQType.A, response.QType);
                Assert.AreEqual(2, response.Answers.Count);

                Assert.IsNotNull(response.Answers.SingleOrDefault(r => ((A_RR)r).Address.Equals(IPAddress.Parse("10.0.0.1"))));
                Assert.IsNotNull(response.Answers.SingleOrDefault(r => ((A_RR)r).Address.Equals(IPAddress.Parse("10.0.0.2"))));
            }
            finally
            {
                if (client != null)
                {
                    client.Close();
                }

                if (handler != null)
                {
                    handler.Stop();
                }
            }
        }
コード例 #3
0
        public void DynDnsService_EndToEnd()
        {
            LeafRouter   router     = null;
            Process      svcProcess = null;
            Assembly     assembly   = typeof(LillTek.Datacenter.DynDnsService.Program).Assembly;
            DynDnsClient client     = null;

            Helper.InitializeApp(assembly);

            try
            {
                Config.SetConfig(@"

&section MsgRouter

    AppName                = LillTek.DynDNS Service
    AppDescription         = Dynamic DNS
    RouterEP			   = physical://DETACHED/$(LillTek.DC.DefHubName)/$(Guid)
    CloudEP                = $(LillTek.DC.CloudEP)
    CloudAdapter           = ANY
    UdpEP				   = ANY:0
    TcpEP				   = ANY:0
    TcpBacklog			   = 100
    TcpDelay			   = off
    BkInterval			   = 1s
    MaxIdle				   = 5m
    EnableP2P              = yes
    AdvertiseTime		   = 1m
    DefMsgTTL			   = 5
    SharedKey		       = PLAINTEXT
    SessionCacheTime       = 2m
    SessionRetries         = 3
    SessionTimeout         = 10s
    MaxLogicalAdvertiseEPs = 256
    DeadRouterTTL          = 2s
    
    // This maps the abstract Dynamic DNS endpoints to their default logical endpoints.

    AbstractMap[abstract://LillTek/DataCenter/DynDNS] = logical://LillTek/DataCenter/DynDNS

&endsection

&section MsgRouter

    AppName                = LillTek.DynDNS Service
    AppDescription         = Dynamic DNS
    RouterEP			   = physical://DETACHED/$(LillTek.DC.DefHubName)/$(Guid)
    CloudEP                = $(LillTek.DC.CloudEP)
    CloudAdapter           = ANY
    UdpEP				   = ANY:0
    TcpEP				   = ANY:0
    TcpBacklog			   = 100
    TcpDelay			   = off
    BkInterval			   = 1s
    MaxIdle				   = 5m
    EnableP2P              = yes
    AdvertiseTime		   = 1m
    DefMsgTTL			   = 5
    SharedKey		       = PLAINTEXT
    SessionCacheTime       = 2m
    SessionRetries         = 3
    SessionTimeout         = 10s
    MaxLogicalAdvertiseEPs = 256
    DeadRouterTTL          = 2s
    
    // This maps the abstract Dynamic DNS endpoints to their default logical endpoints.

    AbstractMap[abstract://LillTek/DataCenter/DynDNS] = logical://LillTek/DataCenter/DynDNS

&endsection

//-----------------------------------------------------------------------------
// Dynamic DNS Service Settings

&section LillTek.Datacenter.DynDNS

    // Specifies the network binding the DNS server should listen on.
    
    NetworkBinding = ANY:DNS

    // Specifies the NetworkBinding the DNS server 
    // should listen on to receive UDP host registration messages
    // from DynDnsClients.

    UdpBinding = ANY:DYNAMIC-DNS
    
    // Controls how the server is to be configured to obtain host
    // registrations from dynamic DNS clients.  The possible values
    // are UDP, CLUSTER, or BOTH.
    
    Mode = UDP

    // Shared symmetric encryption key used to decrypt UDP registration messages
    // sent by DNS clients while in UDP or BOTH mode.  This key must match the shared
    // key configured for the client.  This defaults to the same reasonable default 
    //  used by the DNS client class.

    SharedKey = aes:BcskocQ2W4aIGEemkPsy5dhAxuWllweKLVToK1NoYzg=:5UUVxRPml8L4WH82unR74A==

    // The maximum delta to be allowed between the timestamp of messages received from
    // UDP broadcast clients and servers and the current system time.
    //
    // Messages transmitted between clients and servers in the UDP broadcast cluster are
    // timestamped with the time they were sent (UTC) to avoid replay attacks.  This
    // setting controls which messages will be discarded for being having a timestamp
    // too far in the past or too far into the future.
    //
    // Ideally, this value would represent the maximum time a message could realistically
    // remain in transit on the network (a few seconds), but this setting also needs to
    // account for the possibility that the server system clocks may be out of sync.  So,
    // this value is a tradeoff between security and reliability.

    MessageTTL = 15m

    // Specifies the time-to-live setting to use when replying to
    // DNS queries.  This indicates how long the operating system
    // on the client side should cache the response.
    
    ResponseTTL = 5s
    
    // Indicates whether DNS host lookup failures should be logged
    // as warnings.
    
    LogFailures = yes
    
    &section Cluster
    
        // The cluster's logical base endpoint.  Instance endpoints will be constructed
        // by appending a GUID segment to this and the cluster broadcast endpoint
        // will be generated by appending '/*'.  This setting is required.
        
        ClusterBaseEP = abstract://LillTek/DataCenter/DynDNS
        
        // Specifies the startup mode for the instance.  This can be one of
        // the following values:
        // 
        //      NORMAL          Indicates that the cluster member should go through the normal 
        //                      master election cycle and eventually enter into the MASTER or SLAVE
        //                      state.
        //
        //      OBSERVER        Indicates that the cluster member should immediately enter the
        //                      OBSERVER state and remain there.  Cluster observer state information
        //                      is replicated across the cluster so other instances know
        //                      about these instances but observers will never be elected 
        //                      as the master.
        //
        //      MONITOR         Indicates that the cluster member should immediately enter the 
        //                      MONITOR state and remain there.  Monitors collect and maintain 
        //                      cluster status but do not actively participate in the cluster.  
        //                      No member status information about a monitor will be replicated
        //                      across the cluster.
        //
        //      PREFERSLAVE     Indicates that the cluster member prefers to be started as a 
        //                      cluster slave
        //
        //      PREFERMASTER    Indicates that the cluster member prefers to be started as the 
        //                      cluster master.  If a master is already running and it does not 
        //                      have this preference then a master election will be called.
        
        Mode = Normal

        // The interval at which the cluster master should broadcast cluster update
        // messages.  Default is 1m.
        
        MasterBroadcastInterval = 10s

        // The interval at which slaves send their status updates to the master.
        // Default is 1m.

        SlaveUpdateInterval = 10s

        // The time period cluster members will wait while collecting member status
        // broadcasts from peers before concluding a master election.  Default
        // is 5s.

        ElectionInterval = 10s

        // The number of times a cluster slave member should allow for missed
        // cluster status messages before calling for a master election.
        // Default is 3.

        MissingMasterCount = 2

        // The number of times the cluster master should allow for missed
        // slave status transmissions before removing the slave from the cluster 
        // state.  Default is 3.

        MissingSlaveCount = 2

        // The interval at which the cluster master instance should raise its
        // ClusterMember.MasterTask event so that derived classes can implement 
        // custom background processing behavior.  Default is 1s.

        MasterBkInterval = 1s

        // The interval at which the cluster slaves should raise their
        // ClusterMember.SlaveTask event so that derived classes
        // can implement custom background processing behavior.
        // Default is 1s.

        SlaveBkInterval = 1s

        // The background task polling interval.  This value should be less than
        // or equal to the minimum of MasterBroadcastInterval, MasterBkInterval, 
        // and SlaveBkInterval.  Default is 1s.

        BkInterval = 1s

    &endsection

&endsection

".Replace('&', '#'));

                router = new LeafRouter();
                router.Start();;

                // Start the Dynamic DNS service

                svcProcess = Helper.StartProcess(assembly, "-mode:form -start");
                Thread.Sleep(10000);     // Give the process a chance to spin up

                // Open a dynamic DNS client and register a host and then
                // verify that it worked.

                DynDnsClientSettings clientSettings;

                clientSettings                     = new DynDnsClientSettings();
                clientSettings.Mode                = DynDnsMode.Udp;
                clientSettings.NameServers         = new NetworkBinding[] { new NetworkBinding(NetHelper.GetActiveAdapter(), NetworkPort.DynamicDns) };
                clientSettings.UdpRegisterInterval = TimeSpan.FromSeconds(1);

                client = new DynDnsClient();
                client.Register(new DynDnsHostEntry("test.com", IPAddress.Parse("10.1.2.3")));
                client.Register(new DynDnsHostEntry("www.lilltek.com", IPAddress.Parse("192.168.1.202")));
                client.Open(router, clientSettings);
                Thread.Sleep(3000);

                Assert.AreEqual(IPAddress.Parse("10.1.2.3"), DnsLookup("test.com"));

                // Uncomment this for manual interop testing

                // Thread.Sleep(10000000);
            }
            finally
            {
                if (client != null)
                {
                    client.Close();
                }

                if (svcProcess != null)
                {
                    svcProcess.Kill();
                    svcProcess.Close();
                }

                if (router != null)
                {
                    router.Stop();
                }

                Config.SetConfig(null);
            }
        }
コード例 #4
0
        public void DynDnsHandler_Udp_CNAME()
        {
            // Start a Dynamic DNS service handler and a client, register CNAME
            // records and confirm that CNAME queries return the proper results.

            DynDnsClientSettings clientSettings;
            DynDnsHandler        handler = null;
            DynDnsClient         client  = null;
            DnsResponse          response;
            CNAME_RR             record;

            try
            {
                handler = new DynDnsHandler();
                handler.Start(router, null, null, null);

                clientSettings = new DynDnsClientSettings()
                {
                    Mode                = DynDnsMode.Udp,
                    NameServers         = new NetworkBinding[] { new NetworkBinding("127.0.0.1:DYNAMIC-DNS") },
                    UdpRegisterInterval = TimeSpan.FromSeconds(1)
                };

                client = new DynDnsClient();
                client.Register(new DynDnsHostEntry("test1.com,server.test1.com,1000,CNAME"));
                client.Register(new DynDnsHostEntry("test2.com,server.test2.com,2000,CNAME"));
                client.Open(router, clientSettings);

                // Wait for everything to spin up.

                Thread.Sleep(3000);

                // Verify the single result for a CNAME query on test1.com

                response = DnsResolver.Query(IPAddress.Loopback, new DnsRequest(DnsFlag.NONE, "test1.com.", DnsQType.CNAME), TimeSpan.FromSeconds(2));

                Assert.AreEqual("test1.com.", response.QName);
                Assert.AreEqual(DnsQType.CNAME, response.QType);
                Assert.AreEqual(1, response.Answers.Count);

                record = (CNAME_RR)response.Answers[0];
                Assert.AreEqual("test1.com.", record.RName);
                Assert.AreEqual("server.test1.com.", record.CName);
                Assert.AreEqual(1000, record.TTL);
                Thread.Sleep(2000);

                // Verify the single result for a CNAME query on test2.com

                response = DnsResolver.Query(IPAddress.Loopback, new DnsRequest(DnsFlag.NONE, "test2.com.", DnsQType.CNAME), TimeSpan.FromSeconds(2));

                Assert.AreEqual("test2.com.", response.QName);
                Assert.AreEqual(DnsQType.CNAME, response.QType);
                Assert.AreEqual(1, response.Answers.Count);

                record = (CNAME_RR)response.Answers[0];
                Assert.AreEqual("test2.com.", record.RName);
                Assert.AreEqual("server.test2.com.", record.CName);
                Assert.AreEqual(2000, record.TTL);
            }
            finally
            {
                if (client != null)
                {
                    client.Close();
                }

                if (handler != null)
                {
                    handler.Stop();
                }
            }
        }
コード例 #5
0
        public void DynDnsHandler_Udp_ADDRESS()
        {
            // Start a Dynamic DNS service handler and a client, register two ADDRESS
            // records for TEST1.COM and confirm that A queries load balance across the two entries.
            // I'm also going to add an ADDRESS record for TEST2.COM and verify that this address
            // is never returned.

            DynDnsClientSettings clientSettings;
            DynDnsHandler        handler = null;
            DynDnsClient         client  = null;
            DnsResponse          response;
            A_RR record;
            bool found1;
            bool found2;

            try
            {
                handler = new DynDnsHandler();
                handler.Start(router, null, null, null);

                clientSettings = new DynDnsClientSettings()
                {
                    Mode                = DynDnsMode.Udp,
                    NameServers         = new NetworkBinding[] { new NetworkBinding("127.0.0.1:DYNAMIC-DNS") },
                    UdpRegisterInterval = TimeSpan.FromSeconds(1)
                };

                client = new DynDnsClient();
                client.Register(new DynDnsHostEntry("test1.com,10.0.0.1,1000,ADDRESS"));
                client.Register(new DynDnsHostEntry("test1.com,10.0.0.2,1000,ADDRESS"));
                client.Register(new DynDnsHostEntry("test2.com,10.0.0.3,1000,ADDRESS"));
                client.Open(router, clientSettings);

                // Wait for everything to spin up.

                Thread.Sleep(3000);

                // Loop 1000 times or until we got responses for both entry IP addresses.  Note
                // that there's a 1000:1 chance that this could be working properly and the test
                // still fail.

                found1 = false;
                found2 = false;

                for (int i = 0; i < 1000; i++)
                {
                    response = DnsResolver.Query(IPAddress.Loopback, new DnsRequest(DnsFlag.NONE, "test1.com.", DnsQType.A), TimeSpan.FromSeconds(2));

                    Assert.AreEqual("test1.com.", response.QName);
                    Assert.AreEqual(DnsQType.A, response.QType);
                    Assert.AreEqual(1, response.Answers.Count);

                    record = (A_RR)response.Answers[0];
                    Assert.AreNotEqual(IPAddress.Parse("10.0.0.3"), record.Address);

                    if (IPAddress.Parse("10.0.0.1").Equals(record.Address))
                    {
                        found1 = true;
                    }
                    else if (IPAddress.Parse("10.0.0.2").Equals(record.Address))
                    {
                        found2 = true;
                    }
                    else
                    {
                        Assert.Fail();
                    }

                    if (found1 && found2)
                    {
                        break;
                    }
                }

                Assert.IsTrue(found1);
                Assert.IsTrue(found2);
            }
            finally
            {
                if (client != null)
                {
                    client.Close();
                }

                if (handler != null)
                {
                    handler.Stop();
                }
            }
        }
コード例 #6
0
        public void DynDnsHandler_Cluster_MX()
        {
            // Start a Dynamic DNS service handler and a client, register MX
            // records and confirm that MX queries return the proper results.

            DynDnsHandler handler = null;
            DynDnsClient  client  = null;
            DnsResponse   response;
            MX_RR         record;

            try
            {
                handler = new DynDnsHandler();
                handler.Start(router, null, null, null);

                client = new DynDnsClient();
                client.Register(new DynDnsHostEntry("test1.com,mail1.test1.com,1000,MX"));
                client.Register(new DynDnsHostEntry("test2.com,mail1.test2.com,2000,MX"));
                client.Register(new DynDnsHostEntry("test2.com,mail2.test2.com,3000,MX"));
                client.Open(router, new DynDnsClientSettings("DynDnsClient"));

                // Wait for all cluster members to come online and for
                // the host registrations to be replicated.

                WaitForOnline(handler.Cluster, waitTime);
                WaitForOnline(client.Cluster, waitTime);
                Thread.Sleep(2000);

                // Verify the single result for a MX query on test1.com

                response = DnsResolver.Query(IPAddress.Loopback, new DnsRequest(DnsFlag.NONE, "test1.com.", DnsQType.MX), TimeSpan.FromSeconds(2));

                Assert.AreEqual("test1.com.", response.QName);
                Assert.AreEqual(DnsQType.MX, response.QType);
                Assert.AreEqual(1, response.Answers.Count);

                record = (MX_RR)response.Answers[0];
                Assert.AreEqual("test1.com.", record.RName);
                Assert.AreEqual("mail1.test1.com.", record.Exchange);
                Assert.AreEqual(0, record.Preference);
                Assert.AreEqual(1000, record.TTL);
                Thread.Sleep(2000);

                // Verify the two results for a MX query on test2.com

                response = DnsResolver.Query(IPAddress.Loopback, new DnsRequest(DnsFlag.NONE, "test2.com.", DnsQType.MX), TimeSpan.FromSeconds(2));

                Assert.AreEqual("test2.com.", response.QName);
                Assert.AreEqual(DnsQType.MX, response.QType);
                Assert.AreEqual(2, response.Answers.Count);

                record = (MX_RR)response.Answers.Single(r => ((MX_RR)r).Exchange == "mail1.test2.com.");
                Assert.AreEqual("test2.com.", record.RName);
                Assert.AreEqual("mail1.test2.com.", record.Exchange);
                Assert.AreEqual(0, record.Preference);
                Assert.AreEqual(2000, record.TTL);

                record = (MX_RR)response.Answers.Single(r => ((MX_RR)r).Exchange == "mail2.test2.com.");
                Assert.AreEqual("test2.com.", record.RName);
                Assert.AreEqual("mail2.test2.com.", record.Exchange);
                Assert.AreEqual(0, record.Preference);
                Assert.AreEqual(3000, record.TTL);
            }
            finally
            {
                if (client != null)
                {
                    client.Close();
                }

                if (handler != null)
                {
                    handler.Stop();
                }
            }
        }
コード例 #7
0
        public void DynDnsHandler_Cluster_Basic()
        {
            // Start a Dynamic DNS service handler and then two enabled dynamic DNS
            // clients and one disabled client.
            //
            // Register 2 hosts with different IP addresses on each client and
            // then query the DNS several times for each host to verify that
            // everything worked.
            //
            // Then stop one of the clients and verify that its host registrations
            // are no longer returned in DNS responses.

            DynDnsHandler handler = null;
            DynDnsClient  client1 = null;
            DynDnsClient  client2 = null;
            DynDnsClient  client3 = null;

            try
            {
                handler = new DynDnsHandler();
                handler.Start(router, null, null, null);

                client1 = new DynDnsClient();
                client1.Register(new DynDnsHostEntry("test1.com", IPAddress.Parse("10.0.0.1")));
                client1.Register(new DynDnsHostEntry("test2.com", IPAddress.Parse("10.0.0.2")));
                client1.Open(router, new DynDnsClientSettings("DynDnsClient"));

                client2 = new DynDnsClient();
                client2.Open(router, new DynDnsClientSettings("DynDnsClient"));
                client2.Register(new DynDnsHostEntry("test1.com", IPAddress.Parse("10.0.1.1")));
                client2.Register(new DynDnsHostEntry("test2.com", IPAddress.Parse("10.0.1.2")));

                client3 = new DynDnsClient();
                client3.Open(router, new DynDnsClientSettings("DynDnsClient.Disabled"));
                client3.Register(new DynDnsHostEntry("test1.com", IPAddress.Parse("10.0.3.1")));
                client3.Register(new DynDnsHostEntry("test2.com", IPAddress.Parse("10.0.3.2")));

                // Wait for all cluster members to come online and for
                // the host registrations to be replicated.

                WaitForOnline(handler.Cluster, waitTime);
                WaitForOnline(client1.Cluster, waitTime);
                WaitForOnline(client2.Cluster, waitTime);
                Thread.Sleep(2000);

                // Perform the DNS lookups

                bool found;

                // Test1.com: 10.0.0.1

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.0.1").Equals(DnsLookup("test1.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsTrue(found);

                // Test1.com: 10.0.1.1

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.1.1").Equals(DnsLookup("test1.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsTrue(found);

                // Test2.com: 10.0.0.2

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.0.2").Equals(DnsLookup("test2.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsTrue(found);

                // Test2.com: 10.0.1.2

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.1.2").Equals(DnsLookup("test2.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsTrue(found);

                // Test case insensitivity

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.1.2").Equals(DnsLookup("TEST2.COM")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsTrue(found);

                // Test for name not found.

                try
                {
                    Assert.IsNull(DnsLookup("error.com"));
                    Assert.Fail("Expected a DnsException");
                }
                catch (Exception e)
                {
                    Assert.IsInstanceOfType(e, typeof(DnsException));
                }

                // Make sure that we don't see hosts from client3 since it
                // is disabled.

                // Test1.com: 10.0.3.1

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.3.1").Equals(DnsLookup("test1.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsFalse(found);

                // Close client1 and verify that its registrations are no
                // longer returned but that client2's still are.

                client1.Close();
                client1 = null;
                Thread.Sleep(2000);

                // Test1.com: 10.0.0.1

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.0.1").Equals(DnsLookup("test1.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsFalse(found);

                // Test1.com: 10.0.1.1

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.1.1").Equals(DnsLookup("test1.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsTrue(found);

                // Test2.com: 10.0.0.2

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.0.2").Equals(DnsLookup("test2.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsFalse(found);

                // Test2.com: 10.0.1.2

                found = false;
                for (int i = 0; i < 100; i++)
                {
                    if (IPAddress.Parse("10.0.1.2").Equals(DnsLookup("test2.com")))
                    {
                        found = true;
                        break;
                    }
                }

                Assert.IsTrue(found);
            }
            finally
            {
                if (client1 != null)
                {
                    client1.Close();
                }

                if (client2 != null)
                {
                    client2.Close();
                }

                if (handler != null)
                {
                    handler.Stop();
                }
            }
        }