Checking a port if it's in use/open

[sutee84]

I will check the examples about network.
Does somebody know other way to check if somebody connect to the pc with winvnc (on windows), than check the vnc's port?

[wysota]

The application probably logs a connection to some file in which case you can monitor the log file.

[prof.ebral]

Using threading to handle multiple connections is not a problem, but how do you pass a connection handled by a thread to another process?

I don't know at the moment because that is not what I am working on.

The application probably logs a connection to some file in which case you can monitor the log file.

Please don't tell me you are talking about my application .. if you are, high rating or not check your ego at the source.

EDIT: I think this thread has been unfortunately hijacked. I was just trying to point out that the OP's idea is possible. I didn't mean to hijack his question thread.

[wysota]

I don't know at the moment because that is not what I am working on.

That's the whole point of this discussion. We say this is not possible.

Please don't tell me you are talking about my application .. if you are, high rating or not check your ego at the source.

You may use the threaded or hybrid mode of the thread view to see which post I was replying to.

EDIT: I think this thread has been unfortunately hijacked. I was just trying to point out that the OP's idea is possible. I didn't mean to hijack his question thread.

And we're trying to point out it is not possible so the discussion is not offtopic.

[prof.ebral]

Here is an example of what you want Sutee .. it is coded in Visual Basic so I am not sure how useful it will be to you here.

Link: http://support.microsoft.com/kb/194938

[prof.ebral]

meh. Here is the source for a Network Monitor coded in Qt: http://reachme.web.googlepages.com/qtnetworkmonitor

filetransit.com makes this claim about it

Qt Network Monitor 0.2 is an application to monitor the activity of both LANs and Internet servers, offering you continuous information about all devices: servers, computers, ports, websites, other IP devices, etc.It lets you monitor different devices simultaneously, and generates all types of statistics, obtained from each one of them.

which is also what you want. The site I linked to is the main site for it and it contains the source .. so that might be something to look at Sutee. I can't find the same claim on the main page.

[wysota]

I think you are missing the point of what sutee84 wants to do... He doesn't want to know on which ports there are daemons running, he wants to know when someone connects to one of the running daemons (despite the title of this thread).

[pitonyak]

Take a look at the platform specific results here: http://en.wikipedia.org/wiki/Netstat

This provides incite into how this information is obtained on different operating systems. I am not aware of this functionality being directly available in QT.

[prof.ebral]

You're welcome, Sutee. I don't expect you to use the softwares themselves, instead I thought you would be able to draw some information from them. They are not my softwares so I can verify the claims either. I hope you get what you are looking for.

Some extra info: Firewall Builder is a Qt program that helps you write iptable/netfiler rules. As such it's only for Linux and MacOSX http://www.fwbuilder.org/
But I did some extra research and found an open source Firewall for Windows called Netdefender. This has a Port scanner to scan for open ports: http://www.programmerworld.net/personal/firewall.htm This one is in Visual C++.

Again same premise, draw from it what you can to get what you really want.

[squidge]

After your replies in this forum, I really expected more than the posting of a quick google search. Pointing to the sourcecode of an open-source firewall is hardly practical either, specially considering it is written in Visual C++ and MFC when they were asking for Qt solution. I fail to see why you posted the other links, since they clearly do even less of what was asked.

[wysota]

@fatjuicymole:

Leave them alone, it seems they perfectly know what they want and what they are doing. At some point we have to admit we are just trolling around on this forum and bow our heads before a solution for detecting which tcp (won't work for udp) ports are open by trying to register a listening socket on each and every one of them. Let's face it - resistance is futile and even running a level three diagnostic wouldn't help.

[JD2000]

If you literally wish to see if a port is in use/open then the netstat command is probably what you need.

Variations are built into the kernels of most operating systems.


If you really want to build your own then something based around the pcap library or similar is what you need.

Personally, I would not go there but good luck!

[sutee84]

I solved the problem, I check the log file, it was the easier way.

[squidge]

Does somebody know other way to check if somebody connect to the pc with winvnc (on windows), than check the vnc's port?

Have you taken a look at the VNC source code? The simplest solution may be to modify the code of VNC to popup a message box asking if you wish to accept the connection and show the IP address of the computer thats attempting to connect.