diff --git a/src/Mdns.csproj b/src/Mdns.csproj
index b713e58..368893a 100644
--- a/src/Mdns.csproj
+++ b/src/Mdns.csproj
@@ -20,10 +20,9 @@
     <Description>A simple Multicast Domain Name Service based on RFC 6762.  Can be used as both a client (sending queries) or a server (responding to queries).</Description>
     <PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>
     <PackageReleaseNotes>https://github.com/richardschneider/net-mdns/releases</PackageReleaseNotes>
-    <Copyright>© 2018 Richard Schneider</Copyright>
+    <Copyright>© 2018-2019 Richard Schneider</Copyright>
     <PackageTags>multicast mdns dns zeroconf</PackageTags>
     <IncludeSymbols>True</IncludeSymbols>
-    <PackageLicenseUrl>https://github.com/richardschneider/net-mdns/blob/master/LICENSE</PackageLicenseUrl>
     <PackageProjectUrl>https://github.com/richardschneider/net-mdns</PackageProjectUrl>
   </PropertyGroup>
 
@@ -34,7 +33,7 @@
   <ItemGroup>
     <PackageReference Include="Common.Logging" Version="3.4.1" />
     <PackageReference Include="IPNetwork2" Version="2.1.2" />
-    <PackageReference Include="Makaretu.Dns" Version="1.5.0" />
+    <PackageReference Include="Makaretu.Dns" Version="2.0.0" />
   </ItemGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard14'">
diff --git a/src/MulticastService.cs b/src/MulticastService.cs
index 2a9a348..287a137 100644
--- a/src/MulticastService.cs
+++ b/src/MulticastService.cs
@@ -364,7 +364,7 @@ void checkResponse(object s, MessageEventArgs e)
         /// <exception cref="InvalidOperationException">
         ///   When the service has not started.
         /// </exception>
-        public void SendQuery(string name, DnsClass klass = DnsClass.IN, DnsType type = DnsType.ANY)
+        public void SendQuery(DomainName name, DnsClass klass = DnsClass.IN, DnsType type = DnsType.ANY)
         {
             var msg = new Message
             {
@@ -401,7 +401,7 @@ public void SendQuery(string name, DnsClass klass = DnsClass.IN, DnsType type =
         /// <exception cref="InvalidOperationException">
         ///   When the service has not started.
         /// </exception>
-        public void SendUnicastQuery(string name, DnsClass klass = DnsClass.IN, DnsType type = DnsType.ANY)
+        public void SendUnicastQuery(DomainName name, DnsClass klass = DnsClass.IN, DnsType type = DnsType.ANY)
         {
             var msg = new Message
             {
diff --git a/src/ServiceDiscovery.cs b/src/ServiceDiscovery.cs
index 1a88698..2ca89a0 100644
--- a/src/ServiceDiscovery.cs
+++ b/src/ServiceDiscovery.cs
@@ -14,6 +14,8 @@ namespace Makaretu.Dns
     public class ServiceDiscovery : IDisposable
     {
         static readonly ILog log = LogManager.GetLogger(typeof(ServiceDiscovery));
+        static readonly DomainName LocalDomain = new DomainName("local");
+        static readonly DomainName SubName = new DomainName("_sub");
 
         /// <summary>
         ///   The service discovery service name.
@@ -21,7 +23,8 @@ public class ServiceDiscovery : IDisposable
         /// <value>
         ///   The service name used to enumerate other services.
         /// </value>
-        public const string ServiceName = "_services._dns-sd._udp.local";
+        public static readonly DomainName ServiceName = new DomainName("_services._dns-sd._udp.local");
+
         readonly bool ownsMdns;
         List<ServiceProfile> profiles = new List<ServiceProfile>();
 
@@ -101,7 +104,7 @@ public ServiceDiscovery(MulticastService mdns)
         ///   Use <see cref="QueryAllServices"/> to initiate a DNS-SD question.
         ///   </para>
         /// </remarks>
-        public event EventHandler<string> ServiceDiscovered;
+        public event EventHandler<DomainName> ServiceDiscovered;
 
         /// <summary>
         ///   Raised when a servive instance is discovered.
@@ -162,9 +165,9 @@ public void QueryUnicastAllServices()
         ///   When an answer is received the <see cref="ServiceInstanceDiscovered"/> event is raised.
         /// </remarks>
         /// <seealso cref="ServiceProfile.ServiceName"/>
-        public void QueryServiceInstances(string service)
+        public void QueryServiceInstances(DomainName service)
         {
-            Mdns.SendQuery(service + ".local", type: DnsType.PTR);
+            Mdns.SendQuery(DomainName.Join(service, LocalDomain), type: DnsType.PTR);
         }
 
         /// <summary>
@@ -180,9 +183,14 @@ public void QueryServiceInstances(string service)
         ///   When an answer is received the <see cref="ServiceInstanceDiscovered"/> event is raised.
         /// </remarks>
         /// <seealso cref="ServiceProfile.ServiceName"/>
-        public void QueryServiceInstances(string service, string subtype)
+        public void QueryServiceInstances(DomainName service, string subtype)
         {
-            Mdns.SendQuery($"{subtype}._sub.{service}.local", type: DnsType.PTR);
+            var name = DomainName.Join(
+                new DomainName(subtype),
+                SubName,
+                service,
+                LocalDomain);
+            Mdns.SendQuery(name, type: DnsType.PTR);
         }
 
         /// <summary>
@@ -196,9 +204,9 @@ public void QueryServiceInstances(string service, string subtype)
         ///   When an answer is received the <see cref="ServiceInstanceDiscovered"/> event is raised.
         /// </remarks>
         /// <seealso cref="ServiceProfile.ServiceName"/>
-        public void QueryUnicastServiceInstances(string service)
+        public void QueryUnicastServiceInstances(DomainName service)
         {
-            Mdns.SendUnicastQuery(service + ".local", type: DnsType.PTR);
+            Mdns.SendUnicastQuery(DomainName.Join(service, LocalDomain), type: DnsType.PTR);
         }
 
         /// <summary>
@@ -231,7 +239,10 @@ public void Advertise(ServiceProfile service)
             {
                 var ptr = new PTRRecord
                 {
-                    Name = $"{subtype}._sub.{service.QualifiedServiceName}",
+                    Name = DomainName.Join(
+                        new DomainName(subtype),
+                        SubName,
+                        service.QualifiedServiceName),
                     DomainName = service.FullyQualifiedName
                 };
                 catalog.Add(ptr, authoritative: true);
@@ -289,9 +300,10 @@ void OnAnswer(object sender, MessageEventArgs e)
             }
 
             // Any DNS-SD answers?
+
             var sd = msg.Answers
                 .OfType<PTRRecord>()
-                .Where(ptr => ptr.Name.EndsWith(".local"));
+                .Where(ptr => ptr.Name.IsSubdomainOf(LocalDomain));
             foreach (var ptr in sd)
             {
                 if (ptr.Name == ServiceName)
@@ -364,6 +376,11 @@ void OnQuery(object sender, MessageEventArgs e)
                 response.AdditionalRecords.Clear();
             }
 
+            if (!response.Answers.Any(a => a.Name == ServiceName))
+            {
+                ;
+            }
+
             if (QU)
             {
                 // TODO: Send a Unicast response if required.
diff --git a/src/ServiceInstanceDiscoveryEventArgs.cs b/src/ServiceInstanceDiscoveryEventArgs.cs
index 0724fde..3d70251 100644
--- a/src/ServiceInstanceDiscoveryEventArgs.cs
+++ b/src/ServiceInstanceDiscoveryEventArgs.cs
@@ -17,7 +17,7 @@ public class ServiceInstanceDiscoveryEventArgs : MessageEventArgs
         ///   Typically of the form "<i>instance</i>._<i>service</i>._tcp.local".
         /// </value>
         /// <seealso cref="ServiceProfile.FullyQualifiedName"/>
-        public string ServiceInstanceName { get; set; }
+        public DomainName ServiceInstanceName { get; set; }
     }
 }
 
diff --git a/src/ServiceInstanceShutdownEventArgs.cs b/src/ServiceInstanceShutdownEventArgs.cs
index 20e12c2..b116418 100644
--- a/src/ServiceInstanceShutdownEventArgs.cs
+++ b/src/ServiceInstanceShutdownEventArgs.cs
@@ -17,7 +17,7 @@ public class ServiceInstanceShutdownEventArgs : MessageEventArgs
         ///   Typically of the form "<i>instance</i>._<i>service</i>._tcp.local".
         /// </value>
         /// <seealso cref="ServiceProfile.FullyQualifiedName"/>
-        public string ServiceInstanceName { get; set; }
+        public DomainName ServiceInstanceName { get; set; }
     }
 }
 
diff --git a/src/ServiceProfile.cs b/src/ServiceProfile.cs
index 27f1e2e..3fdf652 100644
--- a/src/ServiceProfile.cs
+++ b/src/ServiceProfile.cs
@@ -50,17 +50,18 @@ public ServiceProfile()
         /// <remarks>
         ///   The SRV, TXT and A/AAAA resoruce records are added to the <see cref="Resources"/>.
         /// </remarks>
-        public ServiceProfile(string instanceName, string serviceName, ushort port, IEnumerable<IPAddress> addresses = null)
+        public ServiceProfile(DomainName instanceName, DomainName serviceName, ushort port, IEnumerable<IPAddress> addresses = null)
         {
             InstanceName = instanceName;
             ServiceName = serviceName;
             var fqn = FullyQualifiedName;
 
-            var simpleServiceName = ServiceName
+            var simpleServiceName = new DomainName(ServiceName.ToString()
                 .Replace("._tcp", "")
                 .Replace("._udp", "")
-                .TrimStart('_');
-            HostName = $"{InstanceName}.{simpleServiceName}.{Domain}";
+                .Trim('_')
+                .Replace("_", "-"));
+            HostName = DomainName.Join(InstanceName, simpleServiceName, Domain);
             Resources.Add(new SRVRecord
             {
                 Name = fqn,
@@ -85,7 +86,7 @@ public ServiceProfile(string instanceName, string serviceName, ushort port, IEnu
         /// <value>
         ///   Always "local".
         /// </value>
-        public string Domain { get; } = "local";
+        public DomainName Domain { get; } = "local";
 
         /// <summary>
         ///   A unique name for the service.
@@ -101,7 +102,7 @@ public ServiceProfile(string instanceName, string serviceName, ushort port, IEnu
         ///   The second label is either "_tcp" (for application
         ///   protocols that run over TCP) or "_udp" (for all others). 
         /// </remarks>
-        public string ServiceName { get; set; }
+        public DomainName ServiceName { get; set; }
 
         /// <summary>
         ///   A unique identifier for the service instance.
@@ -109,7 +110,7 @@ public ServiceProfile(string instanceName, string serviceName, ushort port, IEnu
         /// <value>
         ///   Some unique value.
         /// </value>
-        public string InstanceName { get; set; }
+        public DomainName InstanceName { get; set; }
 
         /// <summary>
         ///   The service name and domain.
@@ -117,7 +118,7 @@ public ServiceProfile(string instanceName, string serviceName, ushort port, IEnu
         /// <value>
         ///   Typically of the form "_<i>service</i>._tcp.local".
         /// </value>
-        public string QualifiedServiceName => $"{ServiceName}.{Domain}";
+        public DomainName QualifiedServiceName => DomainName.Join(ServiceName, Domain);
 
         /// <summary>
         ///   The fully qualified name of the instance's host.
@@ -126,7 +127,7 @@ public ServiceProfile(string instanceName, string serviceName, ushort port, IEnu
         ///   This can be used to query the address records (A and AAAA)
         ///   of the service instance.
         /// </remarks>
-        public string HostName { get; set; }
+        public DomainName HostName { get; set; }
 
         /// <summary>
         ///   The instance name, service name and domain.
@@ -134,7 +135,8 @@ public ServiceProfile(string instanceName, string serviceName, ushort port, IEnu
         /// <value>
         ///   <see cref="InstanceName"/>.<see cref="ServiceName"/>.<see cref="Domain"/>
         /// </value>
-        public string FullyQualifiedName => $"{InstanceName}.{QualifiedServiceName}";
+        public DomainName FullyQualifiedName => 
+            DomainName.Join(InstanceName, ServiceName, Domain);
 
         /// <summary>
         ///   DNS resource records that are used to locate the service instance.
diff --git a/test/MulticastServiceTest.cs b/test/MulticastServiceTest.cs
index d136cfa..d868ab9 100644
--- a/test/MulticastServiceTest.cs
+++ b/test/MulticastServiceTest.cs
@@ -169,6 +169,7 @@ public async Task ReceiveLegacyUnicastAnswer()
                 mdns.Start();
                 Assert.IsTrue(ready.WaitOne(TimeSpan.FromSeconds(1)), "ready timeout");
                 await client.SendAsync(packet, packet.Length, "224.0.0.251", 5353);
+
                 var r = await client.ReceiveAsync();
                 var response = new Message();
                 response.Read(r.Buffer, 0, r.Buffer.Length);
diff --git a/test/ServiceProfileTest.cs b/test/ServiceProfileTest.cs
index 4f0f95e..9a7f009 100644
--- a/test/ServiceProfileTest.cs
+++ b/test/ServiceProfileTest.cs
@@ -102,5 +102,15 @@ public void Subtypes()
             var service = new ServiceProfile("x", "_sdtest._udp", 1024);
             Assert.AreEqual(0, service.Subtypes.Count);
         }
+
+        [TestMethod]
+        public void HostName()
+        {
+            var service = new ServiceProfile("fred", "_foo._tcp", 1024);
+            Assert.AreEqual("fred.foo.local", service.HostName);
+
+            service = new ServiceProfile("fred", "_foo_bar._tcp", 1024);
+            Assert.AreEqual("fred.foo-bar.local", service.HostName);
+        }
     }
 }