Problem in getting DHCPINFORM message response from C#

Question

I am developing an application in which I want to pull out some information through the DHCP server. so I am sending a DHCPINFORM packet on port 67 UDP Broadcast. The problem I am facing is that I am not getting response i.e. DHCPACK or anyother message from DHCP server all the times, means some times it send back an DHCPACK packet at once and some time not at all, what might be cause of this issue?

Here is my network configuration My IP: 192.168.3.31 DHCP Server is at: 192.168.3.108

and C# code I am using is as

private void SendDHCPINFORM()
    {
        UdpClient udpClient = new UdpClient();
        IPEndPoint dhcpClientEndpoint = new IPEndPoint(IPAddress.Broadcast, 67);

        #region Making Data DHCPINFORM
        D_op = 1;
        D_htype = 1;
        D_hlen = 6;
        D_hops = 0;
        D_xid = new byte[4];
        Random objRandom = new Random(8000);
        objRandom.NextBytes(D_xid);

        D_secs = new byte[2];
        D_secs = BitConverter.GetBytes(Convert.ToInt16(0));

        D_flags = new byte[2];
        D_flags = BitConverter.GetBytes(Convert.ToInt16(0));

        D_ciaddr = new byte[4];
        D_ciaddr[0] = 192;
        D_ciaddr[1] = 168;
        D_ciaddr[2] = 3;
        D_ciaddr[3] = 31;

        D_yiaddr = new byte[4];
        D_yiaddr = BitConverter.GetBytes(0);

        D_siaddr = new byte[4];
        D_siaddr = BitConverter.GetBytes(0);

        D_giaddr = new byte[4];
        D_giaddr = BitConverter.GetBytes(0);

        //00-13-D3-D5-27-73
        D_chaddr = new byte[16];
        D_chaddr[0] = 0;
        D_chaddr[1] = 19;
        D_chaddr[2] = 211;
        D_chaddr[3] = 213;
        D_chaddr[4] = 39;
        D_chaddr[5] = 115;

        D_sname = new byte[64];


        D_file = new byte[128];

        M_Cookie = new byte[4];
        M_Cookie[0] = 99;
        M_Cookie[1] = 130;
        M_Cookie[2] = 83;
        M_Cookie[3] = 99;


        D_options = new byte[60];

        //Making DHCPINFORM message
        byte[] messageType = new byte[3];
        messageType[0] = 53;
        messageType[1] = 1;
        messageType[2] = 8; //Message Type from 1-8
        Array.Copy(messageType, D_options, messageType.Length);

        int options_offset = 3;

        byte[] serverIdentifier = new byte[6];
        serverIdentifier[0] = 54;
        serverIdentifier[1] = 4;
        serverIdentifier[2] = 192;
        serverIdentifier[3] = 168;
        serverIdentifier[4] = 3;
        serverIdentifier[5] = 108;
        Array.Copy(serverIdentifier, 0, D_options, options_offset, serverIdentifier.Length);

        options_offset += serverIdentifier.Length;
        byte[] dummyPacket = new byte[3];
        dummyPacket[0] = 116;
        dummyPacket[1] = 1;
        dummyPacket[2] = 1;
        Array.Copy(dummyPacket, 0, D_options, options_offset, dummyPacket.Length);

        options_offset += dummyPacket.Length;
        byte[] clientIdentifier = new byte[9];
        clientIdentifier[0] = 61;
        clientIdentifier[1] = 7;
        clientIdentifier[2] = 1;
        Array.Copy(D_chaddr, 0, clientIdentifier, 3, 6);
        Array.Copy(clientIdentifier, 0, D_options, options_offset, clientIdentifier.Length);

        options_offset += clientIdentifier.Length;
        byte[] hostName = new byte[7];
        hostName[0] = 12;
        hostName[1] = 5;
        Array.Copy(Encoding.ASCII.GetBytes("host1"), 0, hostName, 2, Encoding.ASCII.GetBytes("host1").Length);
        Array.Copy(hostName, 0, D_options, options_offset, hostName.Length);

        options_offset += hostName.Length;
        byte[] vendorClassID = new byte[10];
        vendorClassID[0] = 60;
        vendorClassID[1] = 8;
        //Array.Copy(Encoding.ASCII.GetBytes("Unspecified"), 0, vendorClassID, 2, Encoding.ASCII.GetBytes("Unspecified").Length);
        Array.Copy(Encoding.ASCII.GetBytes("MSFT 5.0"), 0, vendorClassID, 2, Encoding.ASCII.GetBytes("MSFT 5.0").Length);
        Array.Copy(vendorClassID, 0, D_options, options_offset, vendorClassID.Length);

        options_offset += vendorClassID.Length;
        byte[] paramRequestList = new byte[13];
        paramRequestList[0] = 55;
        paramRequestList[1] = 11;
        paramRequestList[2] = 1;
        paramRequestList[3] = 15;
        paramRequestList[4] = 3;
        paramRequestList[5] = 6;
        paramRequestList[6] = 44;
        paramRequestList[7] = 46;
        paramRequestList[8] = 47;
        paramRequestList[9] = 31;
        paramRequestList[10] = 33;
        paramRequestList[11] = 249;
        paramRequestList[12] = 43;
        //Array.Copy(paramRequestList, 0, D_options, 31, paramRequestList.Length);
        Array.Copy(paramRequestList, 0, D_options, options_offset, paramRequestList.Length);

        options_offset += paramRequestList.Length;
        byte[] vendorSpecificInfo = new byte[5];
        vendorSpecificInfo[0] = 43;
        vendorSpecificInfo[1] = 2;
        vendorSpecificInfo[2] = 220;
        vendorSpecificInfo[3] = 0;
        vendorSpecificInfo[4] = 255;
        Array.Copy(vendorSpecificInfo, 0, D_options, options_offset, vendorSpecificInfo.Length);

        byte[] dhcpMessage = new byte[300];
        dhcpMessage[0] = D_op;
        dhcpMessage[1] = D_htype;
        dhcpMessage[2] = D_hlen;
        dhcpMessage[3] = D_hops;

        int destinationIndex = 4;
        Array.Copy(D_xid, 0, dhcpMessage, destinationIndex, D_xid.Length);

        destinationIndex = destinationIndex + D_xid.Length;
        Array.Copy(D_secs, 0, dhcpMessage, destinationIndex, D_secs.Length);

        destinationIndex = destinationIndex + D_secs.Length;
        Array.Copy(D_flags, 0, dhcpMessage, destinationIndex, D_flags.Length);

        destinationIndex = destinationIndex + D_flags.Length;
        Array.Copy(D_ciaddr, 0, dhcpMessage, destinationIndex, D_ciaddr.Length);

        destinationIndex = destinationIndex + D_ciaddr.Length;
        Array.Copy(D_yiaddr, 0, dhcpMessage, destinationIndex, D_yiaddr.Length);

        destinationIndex = destinationIndex + D_yiaddr.Length;
        Array.Copy(D_siaddr, 0, dhcpMessage, destinationIndex, D_siaddr.Length);

        destinationIndex = destinationIndex + D_siaddr.Length;
        Array.Copy(D_giaddr, 0, dhcpMessage, destinationIndex, D_giaddr.Length);

        destinationIndex = destinationIndex + D_giaddr.Length;
        Array.Copy(D_chaddr, 0, dhcpMessage, destinationIndex, D_chaddr.Length);

        destinationIndex = destinationIndex + D_chaddr.Length;
        Array.Copy(D_sname, 0, dhcpMessage, destinationIndex, D_sname.Length);

        destinationIndex = destinationIndex + D_sname.Length;
        Array.Copy(D_file, 0, dhcpMessage, destinationIndex, D_file.Length);

        destinationIndex = destinationIndex + D_file.Length;
        Array.Copy(M_Cookie, 0, dhcpMessage, destinationIndex, M_Cookie.Length);

        destinationIndex = destinationIndex + M_Cookie.Length;
        Array.Copy(D_options, 0, dhcpMessage, destinationIndex, D_options.Length);
        #endregion

        udpClient.Send(dhcpMessage, 300, dhcpClientEndpoint);

        UdpClient udpServerResponse = new UdpClient(68);
        IPEndPoint dhcpServerEndPoint = new IPEndPoint(IPAddress.Any, 0);

        //The following line is receiving the response from DHCP server
        //works some time immediately and some time not even after couple 
        //of minutes and program goes to halt state? Am I making some mistake?
        byte[] dataReceived = udpServerResponse.Receive(ref dhcpServerEndPoint);

        Console.WriteLine("Message Received");
    }

Please help me out?

Answer 1

I don't know really what is the problem but won't it be easier to use the API instead,

DHCP Client API http://msdn.microsoft.com/en-us/library/aa363344(v=VS.85).aspx

DHCP Server Callout API http://msdn.microsoft.com/en-us/library/aa363372(v=VS.85).aspx