i want to get list of Switched on computers in domain. curently i can get list of computers in domain by using directoryentry class but it gives list of all computers in domain whether it is switched on or not. i already reffered 2,3 links on stackoverflow but didnt get answer. pinging takes more time. Is there any efficient solution for this in c# ?
You might want to look at a solution like SCOM for this. It provides a "Heartbeat" functionality which is more reliable than ping (some corporate firewalls might block icmp, e.g. ping traffic). And a bunch of other monitoring stuff. It does mean more management overhead though.
If you want the simplest solution you can't get around ping. Maybe you can use a multithreaded ping like here: https://codereview.stackexchange.com/questions/1202/c-multi-thread-ping
To solve this i simply made a C# app that does a ping to all computers, this can be done very quickly depending on your network.
Basicly what you do is (And what i did):
1) Fetch you network guy
2) Talk to him, ask him if has any "flood protection".
3) If he is not screaming, spawn as many threads as you can and use them ping the machines :).
#Mr Happy already link to code on how to multi thread ping ( Not that its a issue at all).
Related
How to go about to get the process id of a process blocking a certain COM Port on Windows 7 and/or later?
I would like to get the PID programmatically. If possible using Python or C# but the language is not really important, I just want to understand the procedure.
This question has been asked numerous times on SO and many other forums for the last 10 years or so. The generally accepted answer is to use sysinternals to find the process using the particular file handle. Remember, a serial port is really just a file as far as the win32 api is concerned.
So, two answers for you:
Use sysinternals to find to offending application. I don't think this approach will work via python but you might hack something with .NET.
Use the NtQuerySystemInformation in a getHandles function. Take a look at the structures and figure out which fields are useful for identifying the offending process.
os.system("taskkill blah blah blah") against known serial port using apps. More on this idea at the end.
The 2nd idea sounds fun, however I just don't think the juice is worth the squeeze in this case. A relatively small number of processes actually use serial ports these days and if you are working in a specific problem domain, you are well aware of what the applications are called.
I would just run taskkill (via os.system) against any applications that I know 1) can be safely closed and 2) might actually have a port open. With this approach you'll save the headache of enumerating file handles and get back to focusing on what your application should really be doing.
I'm an amateur programmer working on a pet project of mine and I would like some pointers on how to make a C# server application. Here's the general idea:
A client connects to the server application, which in turn fetches the necessary information from a mysql database and sends it back to the client to be displayed and wait for the next action.
I got the idea of making something like this after seeing a somewhat old IBM AS400 mainframe running a warehouse management system, and I though: "Hey, I could try developing a small version of this with a nice UI that doesn't look like it stepped out of a time machine!"
I searched around and used the tcplistener class to communicate between the server and client and managed to send some calls and responses using one thread per client. However I've read that this is not scalable for a large number of clients...
Am I looking at this problem the wrong way and I should try something else? Any input will be appreciated
You don't need to deal with TCP directly for this - WCF (Windows Communication Foundation) was written to abstract all the low level stuff from you.
Check this link out for a good example of how to create a client/server application, it has an entry level explanation, some code and a downloadable project...
http://www.codeproject.com/Articles/16765/WCF-Windows-Communication-Foundation-Example
You can find plenty of information about WCF elsewhere on the internet and here on SO.
It is a very large topic, but the situation you have described is pretty simple - so I doubt you will have problems following the example.
I'm Currenty writing a server architecture and came across this as well: faily easy to solve.
You're right, using 1 thread per client is not effiecient and is a huge waste or resources! The way around that is Thread Pooling. There are loads of different ways to do this but the way I chose to implement it on my server was to add every connection to a queue and then have x number of threads (which you can easily increase or decrease to handle demand) simply dequeue a connection, process it, then enqueue it again.
Of course using WCF will make life easier for you and will speed things up drastically but where's the challange in that!
Ok, the title is my question.
No, this ain't for malware. It is for a parental control program for my own netbook.
Yes, I am tired of my brother's friends visiting porn sites on my laptop when I am away.
Oh, yes, I have red other questions and don't do the "You can't!" thing. It must be possible.
Well, you could run several processes, and when one of them is killed, one of the others would launch a replacement. You can also run a service that would monitor the process and launch another process when the process is killed.
Sorry, I can't comment so I've posted this as a 'answer'.
A few things to consider:
Is a 13 year old or his friends going to notice a process in taskmanager that shouldn't be there? (for example a second explorer.exe, svchost.exe etc.)
What are you trying to actually achieve as there may be other ways to do what it is you want. Are you trying to block them from going on certain sites? Are you trying to monitor what they do? Are you trying to prove to your mum what they are doing? Something else?
Unless you are trying to block them, will they care about anything you may have running? Would they bother to look for 'logging' software running on the PC? I would guess that they wouldn't bother to even open task manager unless the sites weren't working.
If you are trying to give proof or monitor your pc, running a VNC service in the background allows you to connect a viewer from another computer so that you/your mum can watch a live view of what they are up to.
If you want to monitor the sites then you have a wide range of options: keylogging software, browser logging software, proxy software or logging software on your router
If you want to block the sites then you also have a wide range of solutions: hosts file, dns based blocking (e.g. openDNS), blocking software on the pc (e.g. netnanny), blocking software on the router, etc.
Remember: If you are trying to block sites remember that nothing will block 100% of websites. You will only achieve 1 of 2 things: (Ideally) it becomes too much effort trying to find sites not blocked and they use another computer for their porn -or- they persist and find a way around it/to disable it/sites that it doesn't catch
what about unstoppable service ? MSDN
Yes, it is possible, I recently wanted to do the same thing, just came across what is known as Protected Windows Services.
I know this requires a lot of effort but when it's successfully implemented there's no way not even Admin can kill the process.
You'll need to write an additional ELAM Driver for this to work :ELAM Prerequisites - Microsoft Docs
Here is the link where it is described
Register service as protected service
Posted this answer as an Idea ...... If there's any problem I'll delete it.
It has become apparent that where I work needs, internally, a "notification system". The issue being that we are very spread out throughout multiple buildings and the bulk of the work force regularly keeps there email closed for hours at a time.
I need to create a simple way to be able to push out a message and have it "pop up" on everyones computer(or a single computer).
My first thought was to write a windows service that calls a winform/wpf app that resides on each computer that simply pops up with the message. Not sure how viable an idea that is but this is just brain-storming.
A different route, I thought, could be an app that resides in the systray on each computer that polls a db table and using the Query Notifications could pop up a message each time a new row is added. Then simply create an insanely basic app for writing a row to that table.
So, what I am asking is if any one else has walked this path. If so, how?
What things did you take into
consideration?
Are either of my ideas valid starting
points or are "egg and my face in
perfect alignment"?
Is there a different way that is even
simpler?
Thanks
Some simple requirements --> Must be "One Way" as I cannot give our user base a "chat" system. Must be, somewhat, hidden so as to discourage users shutting it off. A la system tray or service.
Wouldn't net send save you reinventing the wheel?
I've never done this but I've worked in a call-centre that did use something similar and they're insanely useful. I remember once when everyone got a message saying "does anyone know Mandarin? HELP ME!!" Brilliant. (Luckily someone did.)
Anyway your ideas are perfectly fine. Personally I'd do this as a client/server application. A windows forms or WPF application that sits in the systray could link to a server using a TCP/IP duplex connection using WCF. Perhaps get the client to register to certain groups depending on the department of the PC it's sitting on.
Then when someone wants to send a message they select which group it needs to go to (or all groups), the message hits the server which sends out to all connected clients, and the WPF app on the computer receives the message and pops it up. You don't even need a database except to store the users/groups, and the message history if you need to.
This might be a ridiculous answer but have you considered implementing a chat system? It's simple to implement and well tested.
Here are some possibilities:
http://messenger.softros.com/
http://en.wikipedia.org/wiki/Instant_messaging#User_base
Article on building your own:
http://www.computerworld.com/s/article/9002059/How_to_build_your_own_corporate_IM_system_
The easiest way to do this is to have a simple client on each machine polling a central service for alerts. Each alert should have a unique id so each client can deal with idempotency (you don't want the central service keeping tabs on which clients have "popped up").
I also recommend having a reasonably short lifespan for each alert, so the client only needs to know a very short list of alerts it has displayed and so if a machine was re-started, only a small history of alerts would be displayed.
With 300 subscribers, you'll want the polling to involve a nice long gap too - you don't really want 300 checks every 10 seconds - so you'll have to balance the technical desire for long gaps between checks with the business requirement to get an alert within a certain timeframe.
You could easily achieve this with a NET/TCP WCF service being polled by either a WINFORM / WPF application that is added as a start up program, or a windows service that then spawns a UI to display the notification.
I did something like this a long time ago to coordinate smoke breaks. I simply sent a broadcast packet out on the LAN at a specific port. Worked relatively well, although since anybody could broadcast and everybody would get a popup, it got abused a lot.
I would recommend you SPARK. We have same problem in my firm and finally decided to save time and do not reinventing the wheel and use existing (freeware) solution. SPARK does the job for us.
"Spark is an Open Source, cross-platform IM client optimized for businesses and organizations. It features built-in support for group chat, telephony integration, and strong security. It also offers a great end-user experience with features like in-line spell checking, group chat room bookmarks, and tabbed conversations."
If you cannot use / install existing IMs you might thing about implementing simple "chat" protocol in your app.
It is quite easy do that base on sockets and many articles available.
For example:
http://www.codeproject.com/KB/IP/TCPIPChat.aspx
http://www.codeproject.com/KB/miscctrl/SimpleMessenger.aspx?display=Print
If you need something advanced (eg. receive historical notification, users status management etc) you can consider using openSource Jabber API:
Eg http://www.codeproject.com/KB/gadgets/googletalk.aspx
I have two unrelated processes that use .NET assemblies as plugins. However, either process can be started/stopped at any time. I can't rely on a particular process being the server. In fact, there may be multiple copies running of one of the processes, but only one of the other.
I initially implemented a solution based off of this article. However, this requires the one implementing the server to be running before the client.
Whats the best way to implement some kind of notification to the server when the client(s) were running first?
Using shared memory is tougher because you'll have to manage the size of the shared memory buffer (or just pre-allocate enough). You'll also have to manually manage the data structures that you put in there. Once you have it tested and working though, it will be easier to use and test because of its simplicity.
If you go the remoting route, you can use the IpcChannel instead of the TCP or HTTP channels for a single system communication using Named Pipes. http://msdn.microsoft.com/en-us/library/4b3scst2.aspx. The problem with this solution is that you'll need to come up with a registry type solution (either in shared memory or some other persistent store) that processes can register their endpoints with. That way, when you're looking for them, you can find a way to query for all the endpoints that are running on the system and you can find what you're looking for. The benefits of going with Remoting are that the serialization and method calling are all pretty straightforward. Also, if you decide to move to multiple machines on a network, you could just flip the switch to use the networking channels instead. The cons are that Remoting can get frustrating unless you clearly separate what are "Remote" calls from what are "Local" calls.
I don't know much about WCF, but that also might be worth looking into. Spider sense says that it probably has a more elegant solution to this problem... maybe.
Alternatively, you can create a "server" process that is separate from all the other processes and that gets launched (use a system Mutex to make sure more than one isn't launched) to act as a go-between and registration hub for all the other processes.
One more thing to look into the Publish-Subscribe model for events (Pub/Sub). This technique helps when you have a listener that is launched before the event source is available, but you don't want to wait to register for the event. The "server" process will handle the event registry to link up the publishers and subscribers.
Why not host the server and the client on both sides, and whoever comes up first gets to be the server? And if the server drops out, the client that is still active switches roles.
There are many ways to handle IPC (.net or not) and via a TCP/HTTP tunnel is one way...but can be a very bad choice (depending on circumstances and enviornment).
Shared memory and named pipes are two ways (and yes they can be done in .Net) that might be better solutions for you. There is also the IPC class in the .Net Framework...but I personally don't like them due to some AppDomain issues...
I agree with Garo.
Using a pub/sub service would be a great solution. This obviously means that this service would need to be up and running before either of the other two.
If you want to skip the pub/sub you can just implement the service in both applications with different end points. When either of the applications is launched it tries to access the other known object via the IPC proxy. If the proxy fails, the other object isn't up.
-Scott
I've spent 2 days meandering through all the options available for IPC while looking for a reliable, simple, and fast way to do full-duplex IPC. IPCLibrary, which I found on Codeplex.com, is so far working perfectly out of all the options that I tried. All with only 7 lines of code. :D If anyone stumbles across this trying to find a full-duplex IPC, save yourself a ton of time and give this library a try. Grab the source code, compile the data.dll and follow the examples given.
HTH,
Circ