1

I posted this question some time ago on stackoverflow, but unfortunately I didn't get any answer yet. It's actually not very urgent, as this problem seems only to exist on my machine - for now. But I've been told, that there have been similar issues on other machines inside our network, when using WMI.

The original question:

So I have this method, that reads the quota of a user:

public ulong GetQuotaLimit(string username, string domain, char volume)
{
    var scope = GetManagementScope(this, @"root\cimv2");
    var path = new ManagementPath(
                        string.Format(
                                      "Win32_DiskQuota.QuotaVolume='Win32_LogicalDisk.DeviceID=\"{0}:\"',User='Win32_Account.Domain=\"{1}\",Name=\"{2}\"'",
                                      volume, domain, username));
    var diskQuotaObj = new ManagementObject(scope, path, null);
    var result = Convert.ToUInt64(diskQuotaObj.Properties["Limit"].Value);
    return result;
}

It runs fine on my colleague's machine (~200ms), but for some reason it doesn't on my own machine - It takes MUCH longer to get a response from the machine, that maintains the user's quota (~2000ms). The specs for both machines are pretty much the same (same OS, same HW) and they are located within the same network and same domain.

So I inspected the network traffic on both machines for this request and found one strange thing: After connection establishment and authenticating my colleague's machine continues straight away with the actual request (starting at frame 491).

192.168.131.95 is the machine, that maintains the quota

192.168.131.175 is my colleague's machine

192.168.144.11 is my machine

The records are filtered by these IPs

enter image description here

But my machine continues with a TCP 3-way handshake (frames 90-92), then waits for a while (which causes the delay) and continues with a second authentication (starting at frame 126), before it finally does what it is supposed to do - sending the actual request.

enter image description here

It seems like the client (my machine) has lost the connection somehow, yet I don't see any frame, that would actually indicate this. I also heard, that WMI has some issues with fragmentation, but the segments/datagrams are actually smaller than fragmentation the usual fragmentation treshold (1500Bytes?) and wireshark did not indicate that frames were reassembled, so this shouldn't be the reason.

Anyone any clue why this behaviour occurs?

0

You must log in to answer this question.

Browse other questions tagged .