I am writing an application where all the request to the internet should go from it like in firewall. so that i can block the request for a particular website. In my case the program will be running on the same machine. I have tried the promiscous method but using that we can only capture all the packets comming and going from the machine,
The easiest way to do it is probably to write a Layered Service Provider (LSP). There is an example in the Microsoft SDK on developing LSPs as well. Not as secure as a driver type firewall setup, but a lot easier to implement.
There's "probably" a way to do it with C#, but I have never tried it. Something to look into. If not then just create a native DLL with C/C++ that implements the LSP then have it communicate with your app.
You have to insert your code in the TCP/IP stack, which, if I understand correctly, requires a windows driver.
C# cannot compile native windows drivers, so you'll need to use a library or DLL to implement at least part of your functionality. Look for solutions using C++.
-Adam
Related
Background:
I have an old vb6 application that I really need to get out of my life. I love coding in c# and want to make an application to replace the old vb6 application.
The vb6 app has a component app that is installed via IIS and that the main GUI vb6 app connects to for various purposes. The reason the COM app/components exist are so that everything done is coming from the same source.
Ex: I'm working remotely and need to connect to an FTP server that is only accessible from my works network. The main GUI app connects to the COM object, issues a command and then that set of components creates the FTP connection from my work network/ip (instead of my home network/ip).
Question:
In replacing this old application GUI and COM object, what is the best approach in c#? Should I still use the old Component Services that I hate so much? Or is there a newer, better way of going about this same task?
There is nothing special about using FTP that would require COM (and certainly writing a GUI in C# does not require COM either).
If I were doing it:
WPF GUI (Future proof for when WinForms is gone... and gives you a leg up with WinRT which also supports XAML).
Nuget in an FTP library, like this one: https://www.nuget.org/packages/Ftp.dll/
Make sure you separate your GUI from your back-end communications through appropriate interfaces/patterns so you can replace things easily and more "future-proof" your application.
Edit:
So, what you're really after is: How can I have a GUI front end that talks to a back end via various means?
So, there's lots of answers to that, and it basically boils down to, either: don't do that, "pick a lane and stick to it", or "Use WCF".
WCF (Windows Communication Framework https://learn.microsoft.com/en-us/dotnet/framework/wcf/whats-wcf ) is a back-end server side technology that supports multiple communication protocols simultaneously, but generally allows you to interact between client and server. SOAP was originally the popular choice, but it also supports Remoting (which you alluded to), you can send attachments via DIME which is then like FTP, or you can roll-your-own and do anything you want (e.g. using Capn Proto (https://capnproto.org/) to send binary messages).
Alternately, if you can get away from trying to do everything, you may want to look into REST instead which is supported by Web API (https://msdn.microsoft.com/en-us/library/dn448365(v=vs.118).aspx ). This will allow you to send lightweight data back and forth, and is, typically, "the way it's done" these days.
Good luck!
I have a Visual C# project on my computer and I would like my users to be able to interact with it through a web browser. I've done my research, and I understand that I will probably use CGI to do this.
However, while I have been able do this with .pl and .cpp files, i can't figure out how to to it with C sharp (.cs) files. Can anyone explain how I would do this?
EDIT: If there is an alternate solution wherein the webpage communicates my C# program as a back-end program, that works, too.
UPDATE: After cancelling with my hosting provider and setting up a home-based web server (windows), I finally got the C# file to run as CGI. Thanks to everyone for your help!
You've got to give us some context ... why wouldn't asp.net be an option? If you simply don't want to run in the context of IIS, you could simply write a windows service (and expose WCF services, or even raw sockets if that's what you need).
edit: in response to the recent comment about the server being UNIX, you can use MONO to run .net code on that server: http://www.mono-project.com/Main_Page
You can either use something like mod_mono or if you'd prefer something different, you can look at manos de mono
First, I assume you have the Mono project compiler and runtime environment installed on your system.
CGI takes place entirely via standard input and standard output. (This is one reason why it is so easy to write CGI scripts in Perl, Python, Ruby, etc. You just start reading standard input as usual, parse the variables, and write whatever output you want the client to see.) Don't forget that you're responsible for the entire header, including Mime type.
If you need something that performs faster than CGI's constant fork(2)+execve(2) re-starting your CLR over and over again, you can implement the FastCGI protocol (at least, I didn't see a C# implementation on the Wikipedia page) yourself using sockets and start your CLR once only, so you have some reasonable performance. (I seem to remember Nat being passionate about the Mono process start time being "fast enough" to use it for interactive commands, so perhaps a lightly-loaded server won't have any trouble with plain old CGI interface.)
I'm starting to write a program which communicates with serial/parallel ports. I'm not sure whether I should write it with C# or C++.
I prefer C# because it's my preferred language and I have written applications (high level) with it. But I'm not sure if it can handle port communication in all circumstances. (For example once I wanted to develop a filter driver and found out it couldn't be done at all using C#. So I'm in doubt about port programming limitations as well.) Usually people go with C++ in these situations. (why?) Is there any limitations in C# I should be aware of regarding this matter?
Since you need fine control over the port (ie, the ability to bit-bang and send raw data), then you need an extra component to do this in .NET. See http://www.lvr.com/parport.htm for an example.
There is no managed way to do this, but by using external components, you can develop in your familiar environment. This is probably the way to go, since dealing directly with ports is a life-consuming process.
I am attempting to implement some additional statistics gathering in a C# server application - I have about 20 or so variables I'd like to be able to report to network monitoring tools; so I am assuming (hopefully correctly) that SNMP is the correct way to go.
There are however two problems:
The application is an open source server that cant include proprietary components, and
It needs to run on Mono under *nix environs as well as Windows via .NET.
The "#SNMP" library at http://sharpsnmplib.codeplex.com/ appears to be a promising solution - but there are no samples I can find; and my knowledge of SNMP is lacking.
Does anyone here have any (quick) examples of reporting data via SNMP? (ideally using a library under the LGPL, X/MIT, BSD or Zlib licenses)
Help much appreciated
Edit:
The problem appears to be a lack of libraries capable of acting as SNMP servers, if anyone is aware of any - this would probably solve the problem nicely.
Edit #2:
Basically I'm looking for a SNMP server library or sample reference implementation.
As the author :) I suggest you check out TestAgent sample. It can send out TRAP or INFORM messages to the IP address you specify.
Note that this is a tiny sample, which does not reveal all powers of SNMP.
#SNMP source comes with some samples (they're actually tests, but one can have an idea about how it works).
Another thing you could try is send your snmp queries calling directly the snmpget executable with the Process class. It's not the best way, but it could work (I've used this kind of approach with another language).
A third-party application reads some Java code from an XML file, and runs it when a certain event happens. In Java, I want to tell a .NET 3.5 application, running on the same machine, that this event occurred. The total data transferred each time is probably a few characters.
What is the best way of using Java to tell the .NET process that something happened?
Java doesn't seem to support Named Pipes on Windows, .NET doesn't natively support memory-mapping, and any solution involving web services or RMI is overkill.
If you don't want the full overhead of RMI, you could do direct socket communcation between the two by opening ports and talking to eachother. You'd have to have some way to have both processes agree on which ports to use, how to handshake/etc, but would be simpler than RMI.
ETA: it looks like you can use named pipes from java, you just can't create them? So if the .NET process would create it, you could read/write to it with java. Java just sees it as a file?