I have two processes running on the same machine. Each process is hosting a WCF service to allow inter process communications asynchronously. As of now, I have assigned a fixed port 8731 and 9000 to the two wcf services. What if a customer machine has these ports taken up? How can i dynamically make the wcf client find the wcf service if I were to dynamically allocate an available port?
Thanks for your help in advance.
I assume you're creating services in code. If you're afraid of the client not having those ports available, you should configure your endpoints using app.config. That way, if a client has an issue with a port, you can simply change their config file instead of recompiling your code.
I am late on this post, but today we have better solution for this problem.
There is a configuration endpoint known as listenUriMode(https://msdn.microsoft.com/en-us/library/system.servicemodel.description.listenurimode(v=vs.110).aspx), if we set this value to "Unique", it will bind hostname to port 0 which will ask OS to assign a free port.
Now client can know about the server port using WCF discovery(https://learn.microsoft.com/en-us/dotnet/framework/wcf/feature-details/wcf-discovery-overview).
Related
I have some requirement where i need to configure WCF service over TCP/IP protocol. I am able to do that by adding end point.
Client which is going to consume service will use some tool to push information. That tool take only IP address and Port Number.
Now i need some way to invoke service method by default on hitting IP with TCP/IP port. Is there any way to implement this? Or any workaround for this?
What i need is that there is some method in service i.e. UploadFile.
Service is using netTCPbinding. I have hosted it on server. so the URL
is something "net.tcp://XXX.XXX.XX.XXX:8080/XXXXServices.svc/mextcp".
Customer is using this for consuming. BUT the problem is my customer
using some tool which accpt only IPAdress and Port No over TCP. I am
trying to configure service in such a way that when he sent, data by
default UploadFile service get called. I hope it's make sense.
Thanks!
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 am new to wcf programming and I have been working on a small project and am having problems with net.tcp port sharing. I am using .net framework 4 and iis 7.
I have two wcf services (serviceA and serviceB) being hosted on our server in separate websites on IIS. Each website has its own .svc file, web.config and bin. If I have each of these services on different net.tcp ports then there is no problem and I can add the service reference to each of them from visual studio on my pc. The services run fine.
However we will soon be starting a project with many more services and we wish to avoid having to open a tcp port for each one so I have been trying to get serviceA and serviceB to port share. If I set them up on the same port then I can access the first service I add but when when I try to access the second service added to the same port i get the following error:
Metadata contains a reference that cannot be resolved:
'net.tcp://myserver/serviceB.svc'. The socket connection was aborted. This
could be caused by an error processing your message or a receive
timeout being exceeded by the remote host, or an underlying network
resource issue. Local socket timeout was **. An
existing connection was forcibly closed by the remote host If the
service is defined in the current solution, try building the solution
and adding the service reference again.
I can not work out what is going wrong. I have done a lot of searching on the subject and I have made sure that the following services are running:
Windows Process Activation Service
Net.Tcp Port Sharing Service
Net.Tcp Listener Adaptor
In addition net.tcp is an enabled protocol in the website's advanced settings. My current best guess is that it might have something to do with how I have defined the net.tcp bindings in IIS manager. Both of my websites running their independant services have the following: 808:*(net.tcp) is this correct?
As i said earlier the tcp services run fine if set up on two separate ports so the issue must be related to the port sharing. Very grateful for any advice
OK I found the problem I was having. In IIS I had set up each service as its own website and was trying to get those different websites to port share. This would not work.
However I found that if I set up just one website and then added my services as seaprate applications under the website then the port sharing will work. This approach lets me have multiple services as applications under one website.
Check this.
This can be helpful to you.
http://himanshudesai.wordpress.com/2011/06/03/multiple-wcf-services-on-a-single-port/
Hope this helps.
I am hosting 3 WCF services inside windows services.Each WCF service contains Multiple endpoints. Right now, i am host all my endpoints thru TCP binding on different ports.
Is there any way to host all these end points from different wcf services on same port?
Sure is! You can use the Net.TCP Port Sharing service.
Net.TCP Port Sharing on MSDN
I just looked into that, out of curiosity. The behavior I discovered seems so strange that I almost don't want to put it here. But it worked in my case, so maybe it's doing the same for you:
I am getting the AddressAlreadyInUseException when I'm trying to host 2 services (i.e., 2 separate ServiceHost instances) on the same net.tcp port with portSharingEnabled="True" set on the netTcpBinding for both. That happens with or without the Net.Tcp Port Sharing Service running. The exception is thrown even if I only start one of the services (and I verified via netstat that there was no other listener on that same port on the machine, plus, I ran the app with elevated privileges).
Now, the funny thing is, the AddressAlreadyInUseException is not thrown when I set PortSharingEnabled = False, and yet both services are fully working!! Once again, with or without the Port Sharing Service running. I could even successfully connect to those services from a different machine.
An important note to make, however, is that the above only applies if the services are hosted within the SAME PROCESS! It does blow up if I try to start another instance of the app that's listening on the same port, but a different base address. But I'm assuming you're hosting those 3 WCF services inside the same Windows Service?
So, even though it doesn't seem right, my answer would be to disable PortSharingEnabled and see if it works with different BaseAddresses on the same port (provided they're all inside the same process).
As far as I know you not only have to enable port sharing on the configuration (or via code), you also have to manually start the Windows Port Sharing service.
That's the reason why I (having similar problem) didn't want to use port sharing, to make it easier for deployment rather than having to mess with other things the user may or may not know.
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.