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C# Calling WCF behind DMZ

I need to call a WCF service that is behind a DMZ:
WEBDMZ .. LANDMZ
------------- ------------
ClientServer => WCF service
As there is a firewall between the two it's not possible for the Client to connect to the WCF service. So I need the WCF service to connect to the client and "listen" to connections or create a tunnel somehow.
I feel it must be a very common problem but I haven't been able to find a proper solution yet. And no it's not possible to open a port. The connection have to be initiated by the WCF.
The client is a server and can easily host any MSMQ or other service.
It seems like this problem can also be referred to as "reverse proxy" or "reverse tunnel".
Solution ideas:
MSMQ hosted by Client (but I'm afraid if it would just simply be polling all the time and creating a network overhead).
A reverse tunnel/proxy?
WCF Duplex?
I'm looking for the simplest solution, preferably in C# and without 3rd party software. Perhaps there is a WCF configuration that allows for reverse calls?

With .Net version 4, you can look at WCF Routing service at here. Or you can build a routing service by yourself following example from Michele Leroux. Here is the link.
EDIT:
You can build a routing service, put it at WEBDMZ server, it will contains list of endpoint wcf service put at DMZ server. At here it will take role as a service server as well as client connect to services at DMZ server. You also can build a discovery service to configure these endpoints automatically.

How can I browse all WCF services on a host?

I want to create a client and a server program using WCF. The communication between them will be TCP. The client will be a windows form where one can insert the host name and then it will list all the servers running on that machine.
Is there a way to do this? I.e. to browse all the WCF services in the machine host?

WCF Discovery - http://msdn.microsoft.com/en-us/library/dd456782.aspx
Windows Communication Foundation (WCF) provides support to enable services to be discoverable at runtime in an interoperable way using the WS-Discovery protocol. WCF services can announce their availability to the network using a multicast message or to a discovery proxy server. Client applications can search the network or a discovery proxy server to find services that meet a set of criteria.
How to: Programmatically Add Discoverability to a WCF Service and Client - http://msdn.microsoft.com/en-us/library/dd456783.aspx

There's no automatic way to do this. There have been various directory service protocols over the years but they've never really taken off. The one that has had most success overall is known as Multicast DNS or zeroconf. However the Windows APIs don't support it very well. Apple supports it under the name Bonjour and Linux supports it under the name Avahi.
The closest Windows equivalent is UPnP SSDP but after some well publicized security vulnerabilities were found, Microsoft dropped support for it by and large. There was an IPv6 rough equivalent known as PNRP (Peer Name Resolution Protocol) but this has also largely fallen out of use.
So, really your choices are to find an mDns library for Windows or to write your own.

WCF client and server

I need multiple clients that talk to a WCF service. The WCF service also must be able to connect to any one of the clients also.
So - it sounds like the server and the clients need to have both a WCF server and client built into each one.
Is this correct or is there some way to do this?
I was looking at NetPeerTcpBinding, but that is obsolete. To be fair I'm not sure if that is a valid solution either.
Background:
I plan to have a Windows service installed on hundreds of machines in our network with a WCF service and a WCF client built in.
I will have one Windows service installed on a server with a WCF service and a client built in.
I will have a Windows Forms application
I will have a database
The clients on the network will connect to the service running on the server in order to insert some information on the database.
The user will use the Windows Forms application to connect to the Windows service on the server and this Windows service will connect to the relevant client on the factory floor (to allow remote browsing of files and folders).
Hence I believe the machines on the floor and the server both require a WCF cleint and service built in.

The reason people are recommending wsHttpDualBinding is because it is in itself a secure and interoperable binding that is designed for use with duplex service contracts that allows both services and clients to send and receive messages.
The type of communication mentioned 'duplex' has several variations. Half and Full are the simplest.
Half Duplex: Works like a walkie-talkie, one person may speak at any given time.
Full Duplex: Like a phone, any person may speak at any given time.
Each will introduce a benefit and a problem, they also provide ways to build this communication more effectively based upon your needs.
I'm slightly confused, but I'll attempt to clarify.
You have an assortment of approaches that may occur here, a Windows Communication Foundation (WCF) Service requires the following:
Address
Binding
Contract
Those are essentially the "ABC's" for WCF. The creation of those depicts a picture like this:
As you can see the Service will contain:
Host
Service
Client
The host houses the service which the client will consume so those service methods perform a desired task. An example representation:
As you see Client-1 is going through the Internet (HTTP, HTTPS, etc.) then will hit the Host, which will have the service perform those tasks.
Now Client-n is consuming the service locally, so it is talking over (TCP, etc.) as an example.
The easiest way to remember: One service can be consumed by however many clients require those methods to perform a task. You can create very complex models using a service-oriented architecture (SOA).
All WCF is, is a mean to connect your application to a host or
centralized location you may not have access to.
As you can see in the above image, the Client communicates through a Service to the Host. Which performs a series of task. WCF will talk over an array of protocols. Hopefully this will provide a better understanding of how WCF is structured.
There are a lot of tutorials and even post to get you started. Some excellent books such as "WCF Step by Step".
Essentially your looking for an asynchronous full duplex connection, or a synchronous full duplex service. As mentioned above, your task in essence is the point of a Service.
The question: How does this work best?
It will boil down to your design. There are limitations and structures that you will need to adhere to to truly optimize it for your goal.
Such obstacles may be:
Server Load
Communication Path
Security
Multiple Clients Altering UI / Same Data
Etc.
The list continues and continues. I'd really look up tutorials or a few books on WCF. Here are a few:
WCF Step by Step
WCF Multi-Tier Development
WCF Service Development
They will help you work with the service structure to adhere to your desired goal.
Remember the "ABCs" for the most success with WCF.

Use wsDualHttpBinding if you want your service communicate with your clients.
Read WS Dual HTTP.

You might want to try out creating a WCF service using netTcpBinding. It will work for your requirements. You can use the article How to: Use netTcpBinding with Windows Authentication and Transport Security in WCF Calling from Windows Forms as a start:
Also, there are many examples included within the WCF Samples package which you can use.

Two way communication using netTCPBinding

I am new to WCF (Just a day or 2). I am planning to make an application having Client/Server
WCF Service (On Server hosted as windows service):
Will invoke some commands using (Process.Start())
Will send some information from my database
Questions:
What WCF binding should I use? WsDualhttp or netTCP (Please elaborate if you can)
Does WCF works with SqlServer + EF 4.1
Server UI:
This will primarily will be used to
Start ot stop the above service
Change Address (localhost to [My Ip address]) and Port
Show status of service (Running or dead)
Questions:
How can I Change the address and port of my WCF service from this UI (it will be a different project and hence different config file).
Client App:
Used to issue commands to WCF service.
Get to know if the service is running or dead.
Receive status messages for task completion or faults.
Also, can the windows installer be combined to install ServerUI + WCF Service + Windows service?

WCF Service
Here are a couple links on choosing the right binding. Based on the scenario you're describing, I'd go with the netTCP.
C# - WCF - inter-process communication
Choosing the right WCF binding
WCF and SQL Server are independent of each other, so I wouldn't expect any problems using the Windows service to interact with your database.
I'd suggest reading up on how to start a process from a Windows service.
Server UI
I would suggest hosting another WCF service in your Windows service for interacting with your Server UI. You can use the netNamedPipeBinding since this communication channel will always be local, i.e., on the same box. So your Windows service will host two WCF services - one for the external communication with the client and one for the local communication with the configuration UI.
Installer
Yes, the Windows installer can be used, but that might be overkill for what you're describing. Of the Server UI, WCF Service, and Windows service, the only one that absolutely requires installation is the Windows service. The others could theoretically run simply by copying the assemblies to the target system. You might consider having the Windows service install itself via command line. That way you could get away with a self-extracting executable using software like WinZip. This might be less heavyweight than a formal install. If you go this route, have a look at the step-by-step here.

Ha a look at WCF duplex services:
http://msdn.microsoft.com/en-us/library/ms731064.aspx
Why do you want to have a interface to an windows service? And if you have access to IIS7 and WAS, I would recommend to use it instead of self-hosting in windows service.
Here is a good starting point for WCF Configuration Management:
http://msdn.microsoft.com/en-us/library/ff650534.aspx
Yes, you can use windows installer.
Cheers
--Jocke

WCF TCP Binding setup between IIS and Service

I developed a WCF service, and now reading about the bindings. It s said that TCP binding is the fastest one, which i like to use, but it requires WCF to WCF communication? What s that exactly means?
I have a an application that s on IIS 7, using ASP.NET and a WCF service. they are on different machines. can i use TCP binding?
When i try tcp binding from client (IIS 7) to WCF service, i m getting connection error.
is it possible to connect to WCF service using only tcp binding from another server with IIS 7?
if there is , how to do it? I open the port on firewall etc. oh , wcftestclient works, my app doesnt. :(
again, CLIENT IS ASP.NET PAGE, SERVICE IS WCF, in the SAME NETWORK.

IIS uses http. So if your intent is to communicate from a WCF client to an ASP.NET application you should use the http binding. In IIS7, you have to manually go through a series of steps to enable non-HTTP bindings, but it's possible. This MSDN article show you how you can do this
http://msdn.microsoft.com/en-us/magazine/cc163357.aspx
If your client application is the ASP.NET application then yes, you should be able to use TCP binding between you ASP.NET application (that is acting as a WCF client) and your other application that is NOT an ASP.NET application but a regular application that is a WCF service
What you might want to try is build a console application as your WCF client using TCP binding and then:
Run it from the same box as your service and ensure things are working correctly.
Run it from the IIS box against your WCF service running on the other box and see if it works.
If both these work then it should work from your ASP.NET application as well.