Here's a scenario that I want to implement using C# or C++.
I want to connect PC-1 to PC-2 over internet and use PC-2 as the gateway for PC-1, so that all the outgoing and incoming traffic to PC-1 gets routed through PC-2. I know about using proxy servers and VPN. But I'd like to implement this on my own using 2 applications, preferably in .NET, that run on these 2 computers.
Edit: I need something similar to a VPN network, when I enable the program in PC-1 it should route entire traffic to PC-2 not just http traffic. I am not sure where to start with.
Any help would be highly appreciated.
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I want to create a simple messaging app that uses tcp protocol to communicate, including with multiple people. Messages get sent to the server, which distributes them to all other clients. At the moment, I have it fully functioning and it works perfectly - on a local computer and a local network, using the ipv4 address.
After an extensive Google search, I discovered that to communicate from a different network I need to port-forward my server. However, how do I make my server able to communicate with clients without all the clients port-forwarding? As far as I'm aware, not everybody's device is port-forwarded.
So, how do I implement this? Is it possible with just C#? Or did I misunderstand something, and port-forwarding isn't really required?
Thanks for all the help.
Why don't you use SignalR. I think it will be best for your problem.
Situation: We have a web application running on a server. This application needs to fetch data from some other PC(Clients), which are on a different network.
On the clients' pc there are WCF hosted in Windows Services using its their local Sql db. i want to make duplex communication between server and clients for share data with each other.
data share mean share data-table,data-set,string etc between clients and server .
Problem :
1) I have no control over the firewall, proxy, NAT on the client side PC. Mostly company Employee PCs have lots of network security e.g firewall block ICMP traffic and some port too, some Router might be Disabled port-forwarding etc etc , client can change network place.
I don't want to make any setting on client side Router,proxy,firewall though .
during communication how can i handle that's kind of issue of client side?
as you know skype is working perfect in that situation.
firewalls very often block inbound connections to clients; the client may not be reachable from the server, it may be using NAT translation behind a router and so cannot be contacted without port forwarding being set up on the router and some new router disabled port forwarding .
2) On clients side there is no IIS .
I don't want to allow remote access on clients PC.
There are more than 100 Clients and only one Server. one server need communicate with many clients on different network .
3) One side my client application is using window application and wcf hosted in window service ,Other side on my server i'm using Web application . so its mean communication is between desktop pc and web pc , that's issue .
If both using a web application then it was not issue to make duplex communication.because i know WEBRTC is fit there lol.
Technology which i had already test and find issue
WSDualHttpBinding: Not work if client behind NAT. check this for detail click here
MSMQ : its bad technique if clients more than 1 and performance issue also because its use RAM memory . check here click here
Xsocket: Its also not work if ICMP traffic block by firewall on client. check here click
WebRTC: Its work fine but its support web to web communication .as my client side i have win app.
Socket.io: Its need to set up node.js and many other thing , hard to implement because i need implement on existence application , i am not making new application.
C# Socket Program: Its wouldn't work if client behind NAT.check here click for detail
Service Bus relay: Its not free even for testing .
socketPro: I studied i find its good but i can't find any right sample on google .so that i could test that.
Genuine Channels: I can't find any sample on google .
Lets see SignalR issue .: Server side i run a console application and Client side i run two application ,one is console and other web. when i was running console client application than it was not initiating connection with Server but when i was using web client application then it was working fine.
sample link is here SignalR two way communication
I can't understand why thas??
Please tell me What is best most secure and fast way to handle this situation? what approach should i use ?
SignalR seems to fit for this solution, because it's flexible.
It negotiates the fastest available channel of communication and that is what you are looking for.
You should investigate the problem with it and signalR will eventually work.
I'm using SignalR extensively to communicate between the servers (C#), between server and mobile apps (C#, Xamarin, iOS, Android). The servers are at different locations and the mobile apps can be anywhere. It all works very reliable.
Take a look at: http://www.asp.net/signalr/overview/deployment/tutorial-signalr-self-host and here http://www.asp.net/signalr/overview/guide-to-the-api/hubs-api-guide-net-client
I've been working in my spare time with sockets (admittedly in c++, not c# but there shouldn't be a difference), and I've never had an issue connecting to clients behind a firewall/router, even without port forwarding.
Routers and firewalls generally don't like server-like programs, eg. programs that bind the socket to a port number. Does your client do anything related to binding? Because it shouldn't.
Needless to say, I would suggest a socket program. The way I see it, it's the most flexible way.
I want all web traffic (HTTP, HTTPS and DNS - Are there any others?) goes through a local application and goes to a server application and from there goes to internet. How can I do this?
I have wrote an Async TCP server and I know socket Async programming in C# using SocketAsyncEventArgs (I am not a master with just one project but I think I can understand some basics).
The only way to do this is to write a Windows network driver - you cannot do this from userland. This is how VPNs work.
There are userland tunnels you can develop that tunnel a single connection, but they require the user to configure their applications to use it first, so you cannot unilaterally redirect all network activity.
From your question, I'm guessing you're not too familiar with Winsock internals or writing kernel network drivers, so for now I'm going to say I think this is a take above your level of competence right now.
However if you'll settle for a bit of an impure approach, you can implement a SOCKS proxy easily enough, but this requires configuring browsers to use your proxy server - at least this way you'll tunnel HTTP and HTTPS, however I'm uncertain about whether or not browsers use SOCKS servers for DNS or if they use the OS-provided DNS functionality.
Like #Dai suggested, use a SOCKS proxy. It operates above the transport layer, therefore a SOCKS server can be configured to serve any application protocol operating on typical TCP/UDP.
This is exactly what TOR does to mask all traffic, not just HTTP.
I'm developing a multiple client / multiple server program in C#, and before I got down to the nitty gritty, I was wondering if anyone has ever worked on a similar project and might be able to share their tips / ideas for implementation.
The servers will sit on many PCs, and listen for incoming connections from clients (Or should the Servers broadcast, and the clients listen?).
When a client starts, it should populate a list of potential server IP addresses automatically.
When a server closes, the client should remove that server from it's list.
When a new server starts, the clients should be notified and have it added to their list.
A server may also act as a client, and should be able to see itself, as well as all other servers.
A message sent from a client to the server, that affects the server, should broadcast the change to all connected clients.
Should my server be a Windows Service? What advantages/disadvantages does that present?
Any ideas on how I might go about getting started on this? I've been looking into UDP Multicast, and LAN Scans. I'm using C# and .NET 4.0
EDIT: Found this: http://code.google.com/p/lidgren-network-gen3/ Does anyone have any experience with it and can recommend/not recommend it?
I would suggest NetPeerTcpBinding WCF communications to create a Peer Mesh. Clients and Servers would all join a mesh using a Peer resolver. You can use PNRP or create a custom peer resolver (.Net actually provides you with an implementation called CustomPeerResolverService). See Peer To Peer Networking documentation.
Also you can implement a Discovery service using DiscoveryProxy. With a discovery service, services can announce their endpoints. The discovery service can then service find requests (see FindCriteria) to return endpoints that match the requests. This is referred to as Managed Discovery. Another mode is Ad Hoc Discovery. Each service will announce their endpoints via UDP and discovery clients will probe the network for these endpoints.
I have actually implemented a Managed Discovery service in combination with Peer 2 Peer WCF networking to provide a redundant mesh of discovery services that all share published service endpoints via P2P. Using Managed Discovery I have found performs far better as Ad Hoc Discovery using UDP probing is slower and has some limitations crossing some network boundaries while Managed Discovery leverages a centralized repository of announced service endpoints.
Either/both technologies I think can lead to your solution.
So is this effectively a peer to peer style network (almost like bittorrent), where all servers are clients, but not all clients are servers.
and the requirements are every client should hold a list of all other servers (which are, in turn, clients).
The problem lies in getting the server IPs to the clients in the first place. You can use a master server that has a fixed DNS to act as a kind of tracker, which all of the servers check in to, and the clients check periodically.
Another option (or an additional method) is to use a peer exchange style system, where each of the clients and servers use UDP broadcast packets over a local network to discover each other and then transfer the servers they know of, kind of like a routing protocol. However if the PCs are spread out over a non local network such as the internet, there's little chance that they will ever discover each other on their own, making this method only useful when used in conjunction with other methods of finding servers. Also, you will probably have to deal with router UPnP to allow clients to connect to each other through each others router NAT, so this method is probably too complex for the gains you get. (However, if you're just on a LAN, this is all you need!)
A third option (and again, this sounds a lot like torrent technology), is to use Distributed Hash Tables to store information about the IPs of your servers in the cloud, without having to rely on a central master server.
I have had a shot at a project like this before (a pure P2P, server-less messaging system), but could never get it to work. Without a huge amount of peers, or a master server to track all of the other servers, it is very difficult to reliably retrieve the IPs of all the servers.
Basically, I want to know how can I intercept/sniff all tcp/udp network traffic for some specific application like the tunneling applications do? For example ProxyCap allows to tunnel all traffic for specific application to some proxy. So as I can understand those programs can intercept all traffic before they change/reroute it.
I've tried using winpcap but even Wireshark. But it doesn't work if you have proxycap installed. I mean, it does not capture application traffic:
Traffic from my program intercepted by the ProxyCap
ProxyCap redirects it all to localhost proxy
My localhost proxy is actually a Your-Freedom gateway proxy
Your-freedom proxy sends traffic to their servers (traffic goes to internet).
When I start Wireshark sniffing (which is based on winpcap driver) I see only traffic from step #4 (when it goes to the internet). And this traffic is not raw (it's packed/encoded) so it doesn't work for me to sniff it.
So since I need to sniff all the traffic I thought that I either find a way to sniff before ProxyCap (or after it, but I don't think it's possible since traffic redirected to the loopback proxy).
I want to ask you guys - is there a way to intercept/sniff traffic like ProxyCap (or other tunneling applications) do?