How can I get all the active TCP connections using .NET Framework (no unmanaged PE import!)?

Question

How can I get all the the active TCP connections using .NET Framework (no unmanaged PE import!)?

I'm getting into socket programming and would like to check this. In my research I found solutions by importing an unmanaged DLL file which I am not interested in.

There are many things that have been made deliberately inaccessible from .net, especially low level things. This has often been done for security reasons so that you know that a dll that only uses managed code cannnot do certain things to your system. — Ben Robinson, Dec 10 '12 at 18:07
Use IPGlobalProperties.GetActiveTcpConnections() in the System.Net.NetworkInformation namespace. — Hans Passant, Dec 10 '12 at 19:00
I'd like to understand the close vote, please be helpful and post the reason — RollRoll, Dec 10 '12 at 20:26

score 33 · Accepted Answer · edited Feb 18 '13 at 09:54

33

I'm surprised with the quantity of users telling me that was not possible to do with pure managed code... For future users who is wondering about that, find the details from the answer that worked fine for me:

//Don't forget this:
using System.Net.NetworkInformation;

public static void ShowActiveTcpConnections()
{
    Console.WriteLine("Active TCP Connections");
    IPGlobalProperties properties = IPGlobalProperties.GetIPGlobalProperties();
    TcpConnectionInformation[] connections = properties.GetActiveTcpConnections();
    foreach (TcpConnectionInformation c in connections)
    {
        Console.WriteLine("{0} <==> {1}",
                          c.LocalEndPoint.ToString(),
                          c.RemoteEndPoint.ToString());
    }
}

And call ShowActiveTcpConnections() to list it, awesome and beautiful.

Source: IPGlobalProperties.GetActiveTcpConnections Method (MSDN)

edited Feb 18 '13 at 09:54

Peter Mortensen

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answered Dec 10 '12 at 19:16

RollRoll

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is this a costfull stuff, for getting tcp connections. ie. I want to use this on live environment behind a web request, is it ok? – mehmet mecek Oct 30 '15 at 13:14
2

I know I am late to the party but you could make it even simpler if this is all you are doing, `foreach(var c in IPGlobalProperties.GetIPGlobalProperties().GetActiveTcpConnections())` – chewpoclypse Jul 30 '16 at 06:35
1

Great answer! but is there any way we can get more info? Like the process responsible for the connections? (As shown in the Resources monitor) – Matheus Rocha Jun 16 '18 at 12:09
Can anyone tell me if IPGlobalProperties.GetActiveTcpConnections() or GetActiveTcpListeners triggers a port scan that could be blocked by the Windows firewall or a GPO on the Active Directory? – Nat Nov 01 '18 at 14:33
@Pierre Use .net core – jjxtra Apr 12 '19 at 00:48
@jjxtra Does the methods exist in .Net Core for PCL? Because Mono Framework kind of does its own thing... I'll give it a shot – Pierre Apr 12 '19 at 05:59

How can I get all the active TCP connections using .NET Framework (no unmanaged PE import!)?

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