I have been investigating about creating a UDP server, at first i though i would have to get a dedicated server as i want to run EXE on the server but i currently have a shared server and i believe most ports are open.
I notice that with the WCF 4.5 (pre release) you can create UDP services, would these work in the same way as a UDP server hence a client could send messages to the UDP service in the same way (i.e. UDPClient class).
I presume this is available in 4.5 only and not 4 / 3.5?
What are the pros and cons of running a UDP server vs WCF service with UDP binding?
As far as hosting the UDP WCF service, can this be done on IIS like a standard WCF HTTP service?
Or a console application is required? Of course if a console app is required or something similar then this doesn't help me as I would still need a dedicated server to host the item. This is where i am a little confused.
Here's what I've read in What’s new in WCF 4.5? UDP transport support:
The binding is not supported in IIS/WAS, since there is still no UDP shared listener for WAS
Related
I'm planning on using a wsDualHttpBinding for a WCF service with callbacks. The clients will be a windows form application communicating to the service over the internet. Obviously I have no control over the firewall on the client side, so I'm wondering what is the proper way to set the ClientBaseAddress on the client side?
Right now in my intiial testing I'm running the service and client on the same pc and i am setting the binding as follows
Dim binding As System.ServiceModel.WSDualHttpBinding = Struct.Endpoint.Binding
binding.ClientBaseAddress = New Uri("http://localhost:6667")
But I have a feeling this won't work when deploying over the internet because "localhost" won't translate to the machine address (much less worrying about NAT translation) and that port might be blocked by the clients firewall.
What is the proper way to handle the base address for callbacks to a remote client?
some one tell me if i do not specify ClientBaseAddress then WCF infratructure creates a default client base address at port 80 which is used for the incoming connections from the service. Since port 80 is usually open to firewalls, things should just work.
so just tell me when win form wcf client apps will run then how can i open my custom port like "6667" and also guide me what library or what approach i should use as a result response should come from client side router
to pc and firewall will not block anything. please discuss this issue with real life scenario how people handle this kind of situation in real life. thanks
The proper way is to use TCP transport instead of HTTP transport. Duplex communication over HTTP requires two HTTP connections - one opened from client to server (that's OK) and second opened from server to client. This can work only in scenarios where you have full control over both ends. There is simply too many complications which cannot be avoided just by guessing what address to use like:
Local Windows or third party firewall has to be configured
Permission for application to run - listening on HTTP is not allowed by default unless UAC is turned off or application is running as admin. You must allow listening on the port through netsh or httpcfg (windows XP and 2003) - that again requires admin permissions.
Port can be already used by another application. In case of 80 it can be used by any local web server - for example IIS.
Private networks and network devices - if your client machine is behind the NAT the port forwarding must be configured but what if you have two machines running your application on the same private network? You cannot forward from the same incoming port to two machines.
All these issues can be avoided mostly only when you have control over whole infrastructure. That is the reason why HTTP duplex communication is useful mostly for intranet scenarios and why for example Silverlight offers another implementation where the second connection is not created and Silverlight client instead polls server continuously to check if there is any callback available.
TCP transport requires only single connection from client to server because TCP protocol is natively duplex so the server can call back the client through the same connection. When you deploy a public service you usually have control over infrastructure on the server side so you can make necessary changes in configuration to make it work.
I think this also answers your previous question.
I have some small questions of which I think they're quite easy to answer for a WCF expert, but which I don't exactly know. I'm hoping they're not to obvious:
Does transport security (http with
ssl) work in conjunction with
streaming? If no, how can I transfer
large data in a secure way to the
client?
If I am not completely off the track
an IDuplexSessionChannel requires
the client to open a port too, so
that the service can contact the
client via a callback. Does this
also affect an IDuplexSessionChannel
which comunicates via http? Port 80
should be open by default, shouldn't
it?
Yes streaming works with HTTPS (basicHttpBinding).
Yes duplex session channel requires port opened on the client because duplex communication over HTTP really means one connection from the client to the server and one reverse connection from the server to the client. Port 80 doesn't have to be opened by default on the client - if it is, it is most probably already associated with some web server so it cannot be used for the communication. Duplex communication is also WCF specific (it is not interoperable) and it leads to other consequences. For example in Windows Vista \ Windows 7 \ Windows 2008 Server with UAC you must run the client with elevated privileges or allow listening on the port by using netsh command line utility.
I'm not sure how these two questions are related but wsDualHttpBinding (implementation of IDuplexSessionChannel) doesn't support streaming or transport security.
How can I configure my WCF service to work as a normal TCP server? Is it possible to disable all that binding specific stuff so as to keep your service URL like http://example.com:4444/service and be able to work vith pure HTTP/TCP streams?
I need to be able to work with TCP streams in tandem with WCF services... so I have to make TCP server from one of my WCF services or (and I do not know how) make my self-hosted WCF services work in pair with my stand alone TCP server. However, I just can not find how to make them share the same port so as to be able to call http://example.com:4444/WCFservice/ http://example.com:4444/TCPserver/ (And I have to make them share it; taking 2 ports is not an option.)
The easiest way to add TCP endpoint to the service is modify you web.config file with respect of "WCF Service configuration editor". You can find it in the "Tools" menu of Visual Studio of in context menu of web.config (also in VS). You need add new endpoint with netTcpBinding. The address of such new endpoint will be start with "net.tcp://". For more information you can read http://msdn.microsoft.com/en-us/library/cc949080.aspx.
For net.tcp port sharing read http://msdn.microsoft.com/en-us/library/aa395195.aspx or google for: wcf tcp endpoint port sharing.
A good review of new features of WCF 4 you can find in http://msdn.microsoft.com/en-us/library/ee354381.aspx
And take it easy if somebody don't understand advantages of WCF compares with Winsocket programming. 15 year ago I used sockets and find it cool. Then I used RPC, DCOM etc. Now WCF is the best way if you think about authentication of your endpoint. So take some of previous comments easy.
If you want to work with pure TCP streams you'd probably work with sockets directly and not WCF.
Use WCF when you want things auto implemented for you at the transport layer.
I've got a WCF service on a server on one side of a firewall. I need to access the service from many workstations on the other side of the firewall. The network guys insist that all holes through the firewall are one-to-one so at the mo, I'll have to set up every workstation one by one. There could be loads and it'll get tedious and be prone to errors.
Is it possible to set up a WCF server on this side of the firewall that can in some clever way just act as a proxy to the 'real' WCF service on the other side of the firewall? If so, could you point me to some reference material?
There is a new concept of a WCF Relay service being developed for the Windows Azure "cloud" computing space. That would allow you to create your scenario fairly easily - just host some bits of your service out in the cloud.
See these links for more information:
WCF services hosted on Windows Azure
Software in the cloud: the Relay service
.NET ServiceBus: Hands-On with Relays
or search Google for "WCF Relay Service". There are also a number of new bindings specifically for these WCF scenarios.
Hope this helps.
Marc
UPDATE:
WCF v4 - to be released with .NET 4.0 later this year (2009) will include a RoutingService class which can be used in scenarios like this.
See more info about the WCF4 routing service here:
Content based routing in WCF 4
Routing messages in WCF 4.0
A developer's introduction to WCF .NET 4 Beta 1
I have a few suggestions, maybe one would work in your case:
Place the WCF service outside the firewall. If the WCF service needs to talk to the database, open the database port for the IP address of the machine running the WCF service.
Program or use code generation to create a WCF service that is simply a pass through layer
There may be some functionality in your firewall that allows you to publish an end point
I need to create a self-hosted WCF service.
I need secure duplex connection between client and server through Internet.
I read some documents of WCF and found that the netTcpBinding is suitable for intranet application, because the SSL is only point 2 point. If it is an internet application, the connection must not be point 2 point, am I correct? so SSL in transport security with netTcpBinding is not suitable?
so what combination should I use to create a secure duplex internet application?
thank you very much.
I have tried http://www.codeproject.com/KB/WCF/WCFWPFChat.aspx
this tutorial use netTcpBinding and endpoint localhost
I change the endpoint localhost to a name based url, forward a port in my router to my development PC, open the same port at Windows firewall.
The client program can chat with each cients program in different machines, BUT the callback connection will lost after one minute.
I also tried changing the binding to wsDualHttpBinding, the clients program can chat with each clients in the same machine and kept the callback connection in the reliableSession inactivityTimeout setting. However another client program in another machine cannot join the server, if I turn off Windows firewall on that machine, the client program can connect.
It seems that tcp binding can let the client program connecting to the server with Windows firewall turn on. but callback connection lost.
and the wsDualHttpBinding can keep the callback connections. but cannot connect to server if Windows firewall on.
Is there a way to kept the netTcpBinding callback connection as in the wsDualHttpBinding?
It sounds like you have two issues- duplex connection and security.
If you truly need a duplex connection (eg, server-initiated callbacks), neither of these will work very well over the internet unless you have very fine control over the firewalls on both ends (the client still has to expose a publicly accessible HTTP endpoint for the server to call back). The best way would be to use the new relay services with .NET 4.0- this allows for a mimic'd server-initiated connection through firewalls.
EDIT: this is now called AppFabric, and is part of the Windows Azure infrastructure
On the security front, you can always use message security over the service bus, but I don't see a reason why transport security would be a problem either.
To answer user248724,
The client program can chat with each
cients program in different machines,
BUT the callback connection will lost
after one minute.after one minute.
You need either have the client or the server to ping each other at least every minute to keep the connection socket alive.