diff --git a/Facepunch.Steamworks/Client/ClientAuth.cs b/Facepunch.Steamworks/Client/ClientAuth.cs
index 272d27c..5479fde 100644
--- a/Facepunch.Steamworks/Client/ClientAuth.cs
+++ b/Facepunch.Steamworks/Client/ClientAuth.cs
@@ -7,11 +7,9 @@ internal class ClientAuth : Auth
     {
         private Client _client;
 
-        public ClientAuth( Client client )
+        public ClientAuth( Client client ) : base( client )
         {
             _client = client;
-            _client.RegisterCallback<SteamNative.ValidateAuthTicketResponse_t>( OnAuthTicketValidate );
-            _client.RegisterCallback<SteamNative.GetAuthSessionTicketResponse_t>( OnGetAuthSessionTicketResponseThing );
         }
 
         public unsafe override Ticket GetAuthSessionTicket()
diff --git a/Facepunch.Steamworks/Interfaces/Auth.cs b/Facepunch.Steamworks/Interfaces/Auth.cs
index fffc079..0f10a75 100644
--- a/Facepunch.Steamworks/Interfaces/Auth.cs
+++ b/Facepunch.Steamworks/Interfaces/Auth.cs
@@ -33,6 +33,12 @@ public enum AuthStatus : int
             PublisherIssuedBan = SteamNative.AuthSessionResponse.PublisherIssuedBan
         }
 
+        public Auth( BaseSteamworks instance )
+        {
+            instance.RegisterCallback<SteamNative.ValidateAuthTicketResponse_t>( OnAuthTicketValidate );
+            instance.RegisterCallback<SteamNative.GetAuthSessionTicketResponse_t>( OnGetAuthSessionTicketResponseThing );
+        }
+
         /// <summary>
         /// This is ran whenever the status of an ongoing session changes
         /// SteamId, OwnerSteamId, Status
diff --git a/Facepunch.Steamworks/Server/ServerAuth.cs b/Facepunch.Steamworks/Server/ServerAuth.cs
index 94e47c4..ffe1a50 100644
--- a/Facepunch.Steamworks/Server/ServerAuth.cs
+++ b/Facepunch.Steamworks/Server/ServerAuth.cs
@@ -7,11 +7,9 @@ internal class ServerAuth : Auth
     {
         private Server _server;
 
-        public ServerAuth( Server server )
+        public ServerAuth( Server server ) : base( server )
         {
             _server = server;
-            _server.RegisterCallback<SteamNative.ValidateAuthTicketResponse_t>( OnAuthTicketValidate );
-            _server.RegisterCallback<SteamNative.GetAuthSessionTicketResponse_t>( OnGetAuthSessionTicketResponseThing );
         }
 
         public unsafe override Ticket GetAuthSessionTicket()