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Is it possible that we could communicate C++ program in linux to a C# program acting as server using Remote Method Invocation?

Is it possible to implement client/server communication between a C++ program (client program) running in linux OS with a C# program(server program) running in Windows using RMI implementation?Can anyone suggest any possible way...Any kind of helpful reference is welcome

You would need to go along the lines of Google Protobuf. It is available with C++ and C# as well.
A similar answer from MSDN
It does not matter if you send data from java,c++ or c#, when it goes
over the network it's just 1s and 0s. It's a matter of what you do
with it on the client/server side. So, be sure that the data that you
receive corresponds with the structure that you have (that you want to
deserialize to).
Sometimes you need to manually put the bits and bytes together to get
it all working out. However, there is something called "Protobuff"
that can help you get a common structure of the data that you send,
google it and read all about it.
You can implement client server with sockets and serialize/deserialize it using protobuf.
(MSDN link might help in solution)

I think message passing libraries would fit best in to this. Take a look at ZMQ for instance; they have binding for many languages found here
so you may have your event dispatcher in one language and listener in the other language. Also take a look at apache thrift

CORBA is one IPC mechanism that will provide the RPC mechanism that you are looking for.
Here is a link describing communication between C# server and JAVA client.
http://iiop-net.sourceforge.net/dnAdderRmiClient.html
At one of the companies I worked previously, it was used for communication between c++ and java programs in a client/server model.
They used a combination of ACE/TAO libraries.
http://www.cs.wustl.edu/~schmidt/TAO.html

I would recommend that you do not use remote method invocation for communication between a client and a server. In the nineteen-nineties we used to believe that RMI is a good idea, but since then we have realized that there are much better ways for communication between computers.
The most popular way is by using Web Services, and the easiest flavor of Web Services is RESTful Web Services. (Look them up.) This has the benefit of not caring at all whether the runtime environment of the client looks anything like the runtime environment of the server, as the case is with your setup, where your client is C++ on Linux and your server is C# on Windows.

Mozilla's XPCOM might be your bridge. There is also PyXPCOM. Realistically though the easiest way is to have an intermediate VBox. So you run a VBox instance (running Windows) on the linux machine and then use VBox API (from C++) to issue commands within VBox. So you end up with
Linux <--xpCom--> VBox <--COM--> Windows

When working over network it's protocol what matters, not the client/server.
In telecommunications, a communications protocol is a system of rules that allow two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. These are the rules or standard that defines the syntax, semantics and synchronization of communication and possible error recovery methods.
Source Emphasis is mine.
So, in order to communicate your C++ client and C# server you need to choose or define protocol that will be used for communication.
Your protocol can be build above another protocol. For example, you can use HTTP for transportation purposes and define your protocol describing what syntax should be used for messages in HTTP requests and responses bodies. This will help you, because there're many ready-to-use solutions for HTTP communication.
Actually you will build your protocol based on another anyway. HTTP itself build above TCP. You'll need to choose whether it would be low level or high level protocols. They all have their pros and cons.
But you will have to deal with messaging between your client and server yourself.
As an alternative you can use some Remote Procedure Call(or RPC) solution:
Remote procedure call (RPC) is an inter-process communication that allows a computer program to cause a subroutine or procedure to execute in another address space (commonly on another computer on a shared network) without the programmer explicitly coding the details for this remote interaction.
So that means that you only have to follow guidelines how to build your client and server and all communication will be hidden and will look like as just calling object's method.
Source
Here's short list of possible RPC solutions:
Component Object Model with DCOM. Wiki: COM,DCOM. MSDN: COM, DCOM.
Simple Object Access Protocol. Wiki.
Windows Communication Foundation. Wiki. MSDN. SO(credits to Sanju for link).
To wrap it up:
It's not a problem that your client and server are in different environments and are developed using different platforms. You only have to build communications between them using either your own messaging system based on some protocol, or some RPC system.

We could just write a C# program to listen messages from a particular port and write another C++ client program to write message to that port.As thus we could communicate both application.

can we sniff some program's network traffic?

I want to develop a program in c# that can target and application or port's traffic and tries to view that traffic.For example,I select example.exe program in my application and it gives me it's network traffic data.
Is it possible?If so,give me some directions.
I'm trying not to use airPcap or winPcap or anything like these,because these libraries target the network card and I don't know what type of interface card the user might be using.

You have to either capture packets where you receive a duplicate from the NIC (pcap), or route requests through your own application so you can inspect the live packet flow (proxy-like).
For a WinPcap implementation in C#, take a look at SharpPcap. For a proxy, see here.

winPcap is a very good library for what you want to do.
If you choose to do it yourself, you will only be reinventing the wheel, and might not be able to support as many network cards as it does.
If you only want to see the traffic, you would have to use a proxy in between.
But I believe you are not looking to build something like, fiddler for example,
that sits in between and allows you to monitor the traffic.

If I understand you correctly you want make a c# app where you select from a list of running applications and display the network traffic to/from that app. You could do this with c# but you would have to make calls to the Windows API to get the information you need. In addition you will need non-c# library for packet capture sucgh as WinPcap. Windows has a new NetMon API that does pcap like things. I have not used it, but you probably way better off with pcap and the SharpPcap lib that CodeCaster posted.

How to approach Android development in C# where the app will need internet access?

I will need to begin development on an Android applicaiton soon. This application will need to communicate with a server over the internet. I hope to be able to do my development in C# in one of the various development environments that appear to be available, e.g. Mono for Android.
My questions are:
What is the best framework for developing C# applications for Android?
What will give me the most flexibility for communicating over the Internet? (My boss tells me that existing c# --> Android frameworks have limitations regarding internet access)
What are the limitations that I can expect to face doing this with C#?
What are your experiences with taking this approach?

For communication over internet there might be many ways, depends on your needs.
It can be HTTP requests with some POST data, or proper low-level communication over Sockets.
If you need to communicate with web service that accepts POST requests and provides some data in XML (for example), then you might use HTTP request way.
If you have real-time server that servers Sockets communication, then you might want to use Sockets with some data protocol over it (based on which data protocol server accepts / serves).
There is full support for establishing Sockets communication using MonoDroid with. It is almost the same as with x86 .Net implementation on Windows.

HTML5 WebSockets Client for .NET

So,
I found that amazing thing called HTML5 WebSockets, new API. That is still in DRAFT version, but quite well supported. Full-duplex bi-directional communication. I know how to use it via JavaScript, there is APIs. But if I want to use a WebSocket client within my C#/.NET application, how to do that?
For example JavaScript: http://bohuco.net/blog/2010/07/html5-websockets-example/
Are there are any special client libraries for WebSockets in .NET?

sir
SuperWebSocket include a WebSocket server implementation and a WebSocket client implementation.
SuperWebSocket's project page

I've recently done some research into this whilst building a .NET and Silverlight client library for Pusher. I found the following WebSocket client libraries and projects:
Microsoft WebSocket client prototype
SuperWebSocket note: there is a client in there, it's just difficult to find
WebSocket-Sharp
Anaida
For the moment the Microsoft implementation is probably the easiest to use and it also has a Silverlight library. SuperWebSockets has a Silverlight project in the source but not in the latest drop.

Starting from .NET 4.5, WebSocket clients are supported via System.Net.WebSockets.ClientWebSocket
You can browse or download this sample C# app from MSDN Code website: http://code.msdn.microsoft.com/WebSockets-middle-tier-5b2972ce/sourcecode.
To the down-voters of the question, the sample is mainly focused on connecting to WebSocket services, which is another significant use-case for a network-centric C# application.

I haven´t tried the Microsoft implementation, but I think Xsockets has the fastest setup time (nuget package). Under 3 min from start to running a complete socketserver + client (demo chat application). Youtube demo
It has fallback to Silverlight and flash for older browsers.

You could use http://www.nuget.org/packages/Microsoft.AspNet.SignalR/ or http://www.asp.net/signalr
ASP.NET SignalR is a new library for ASP.NET developers that makes developing real-time web functionality easy. SignalR allows bi-directional communication between server and side. Servers can now push content to connected cliently instantly as it becomes available. SignalR supports Web Sockets, and falls back to other compatible techniques for older browsers. SignalR includes APIs for connection management (for instance, connect and disconnect events), grouping connections, and authorization.

A friend an I just released a very lightweight, lean, scalable C# websocket server: https://github.com/Olivine-Labs/Alchemy-Websockets
We built it to use in our online game, so our top concern was the quick and efficient handling of tons of connections. It's, from my research, the most efficient out there. And, as a bonus, it supports flash websockets as a fallback for users without websocket-enabled browsers.

If you're looking for a high performance enterprise WebSocket server, take a look at Kaazing. Kaazing has complete support for .NET including Xamarin.
Here is a step-by-step tutorial for AMQP: Checklist: Build Microsoft .NET AMQP Clients.
[Disclosure: I work for Kaazing.]

Yes, you will need an intermediary server which supports the WebSocket protocol. This server could be written in any language including .NET. Here's one for .NET but it really could be any language. As far as your site is concerned it could be ASP.NET and the client part in javascript which will talk to the WebSocket server.

I'm deploying XSockets.net. The framework works quite good, it is being maintained, the developers offer paid support but for normal issues they are also quite active here in SO and they help a lot.
They offer a .net API for implementing the sockets and also a javascript API for the client.
As a summary, I can recommend it.

You have a few choices
Roll your own - the spec is fairly simple
Use someone else's experimental version, such as this one C# Web socket server
Look into the MS WCF approach

Windows Mobile (C#) - Communicating between phone and PC

I'm working on a project where a program running on the mobile phone needs to communicate with a program running on the PC it's connected to. Ideally, I'd like to use USB, WiFi, whatever to communicate.
The two programs should be able to communicate things like battery life, text messages, etc... But I can work on that later, I just need to get them to talk.
What's the best way to do this?

Assuming you have a wifi connection, one way for your Windows Mobile program to communicate with your PC would be to use WCF on the .NET compact framework 3.5.
You'd create a new WCF application to run you your PC, and expose an interface exposing functions you want to call from your Windows Mobile Device.
WCF on Windows Mobile requires Compact Framework 3.5 to be installed on your device.
You also need the "Windows Mobile power toys" to be able to generate compatible proxies to call from Windows mobile.
Power Toys for .NET Compact Framework 3.5
Calling the WCF service from your WM Device also requires you to manually set up the binding and endpoint to pass into your web service proxy (with desktop WCF this is done automatically by loading them from a config file).
WCF on Windows Mobile currently only supports the basic http binding (which can be encrypted if you want), but this may be enough for your needs.

"Best" is really subjective and highly dependent on a lot of factors like devices, topology, firewall presence, need for security, etc, etc.
Where do you need the comms to originate and will you have an ActiveSync connection? If the PC initiates the comms and you have ActiveSync, then RAPI is the transport you'd use as it's got all of the infrastructure done and ready.
For anything else you're going to need some form of proprietary protocol and transport mechanism. Typically I write a simple socket protocol with a defined message structure (typically a message ID, CRC, message length and data payload). I then have some base message class that handles the comms and a set of derived messages for each specific command I want. For 2-way stuff that requires a response, I typically create a base Response class and then derive specific response formats from it.

You might try looking into the OpeNETCF.Desktop.Communications library. You can start at http://www.opennetcf.com/FreeSoftware/tabid/84/Default.aspx and follow the links to find the necessary downloads. (I think you may need to get it from their subversion repository).

WIMO is working on WiFi to desktop support and may be done. Might be worth a look at the code either way.
home
source

found this in 2015, so I don't think the answer is going to be relevant for the original asker, but for the record:
Proximity
https://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh465205.aspx