无法从主机名找到IP

Question

我有一个无线传感器模块(SN8200 EVK)运行一个EVK服务器。该板被配置为作为STA工作，并自动加入WiFi路由器。传感器板使用主机名：“传感器”和DHCP接口来获取其IP地址。

我正在开发一个visual C#应用程序来连接到这个this服务器。应用程序在连接到同一个WiFi路由器的膝上型计算机上运行。

WiFi路由器<

如果我使用板IP地址，应用程序可以连接到传感器板。由于IP地址不是静态的，所以我想使用主机名来检索IP。

我试着使用GetHostEntry，但是得到了未知的主机结果。

IPHostEntry host;
host = Dns.GetHostEntry("sensor");

奇怪的是，如果我在IP地址中使用GetHostEntry，它也不能解析主机名。

如果我尝试使用笔记本主机名或IP，GetHostEntry可以正常工作。看起来GetHostEntry无法解析路由器后面的主机名。

任何帮助都欢迎，谢谢。

Answer 1

静态IP解决方案

First :

在Wifi路由器中配置DHCP服务器内的固定IP地址。

PS :我很确定Mac地址不是动态的

第二版:

使用以前固定的IP地址在DNS服务器中添加主机名。

扫描网络以查找IP并检查Mac地址解决方案

在使用下面的代码之前，您必须对传感器板可以使用的全部IP进行ping，以刷新ARP缓存。

using System;
using System.Runtime.InteropServices;
using System.ComponentModel;
using System.Net;
using System.Collections.Generic;

namespace GetIpNetTable
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] ips = searchIpsFromMac("ff-ff-ff-ff-ff-ff");
            if (ips.Length != 0)
            {
                foreach (string ip in ips)
                {
                    // TODO - Do what you want with your IP address
                    Console.WriteLine(ip);
                }
            }
            Console.ReadKey();
        }

        // The max number of physical addresses.
        const int MAXLEN_PHYSADDR = 8;

        // Define the MIB_IPNETROW structure.
        [StructLayout(LayoutKind.Sequential)]
        struct MIB_IPNETROW
        {
            [MarshalAs(UnmanagedType.U4)]
            public int dwIndex;
            [MarshalAs(UnmanagedType.U4)]
            public int dwPhysAddrLen;
            [MarshalAs(UnmanagedType.U1)]
            public byte mac0;
            [MarshalAs(UnmanagedType.U1)]
            public byte mac1;
            [MarshalAs(UnmanagedType.U1)]
            public byte mac2;
            [MarshalAs(UnmanagedType.U1)]
            public byte mac3;
            [MarshalAs(UnmanagedType.U1)]
            public byte mac4;
            [MarshalAs(UnmanagedType.U1)]
            public byte mac5;
            [MarshalAs(UnmanagedType.U1)]
            public byte mac6;
            [MarshalAs(UnmanagedType.U1)]
            public byte mac7;
            [MarshalAs(UnmanagedType.U4)]
            public int dwAddr;
            [MarshalAs(UnmanagedType.U4)]
            public int dwType;
        }

        // Declare the GetIpNetTable function.
        [DllImport("IpHlpApi.dll")]
        [return: MarshalAs(UnmanagedType.U4)]
        static extern int GetIpNetTable(
           IntPtr pIpNetTable,
           [MarshalAs(UnmanagedType.U4)]
         ref int pdwSize,
           bool bOrder);

        [DllImport("IpHlpApi.dll", SetLastError = true, CharSet = CharSet.Auto)]
        internal static extern int FreeMibTable(IntPtr plpNetTable);

        // The insufficient buffer error.
        const int ERROR_INSUFFICIENT_BUFFER = 122;

        static string[] searchIpsFromMac(string macSearched)
        {
            List<string> ips = new List<string>(1);

            // The number of bytes needed.
            int bytesNeeded = 0;

            // The result from the API call.
            int result = GetIpNetTable(IntPtr.Zero, ref bytesNeeded, false);

            // Call the function, expecting an insufficient buffer.
            if (result != ERROR_INSUFFICIENT_BUFFER)
            {
                // Throw an exception.
                throw new Win32Exception(result);
            }

            // Allocate the memory, do it in a try/finally block, to ensure
            // that it is released.
            IntPtr buffer = IntPtr.Zero;

            // Try/finally.
            try
            {
                // Allocate the memory.
                buffer = Marshal.AllocCoTaskMem(bytesNeeded);

                // Make the call again. If it did not succeed, then
                // raise an error.
                result = GetIpNetTable(buffer, ref bytesNeeded, false);

                // If the result is not 0 (no error), then throw an exception.
                if (result != 0)
                {
                    // Throw an exception.
                    throw new Win32Exception(result);
                }

                // Now we have the buffer, we have to marshal it. We can read
                // the first 4 bytes to get the length of the buffer.
                int entries = Marshal.ReadInt32(buffer);

                // Increment the memory pointer by the size of the int.
                IntPtr currentBuffer = new IntPtr(buffer.ToInt64() +
                   Marshal.SizeOf(typeof(int)));

                // Allocate an array of entries.
                MIB_IPNETROW[] table = new MIB_IPNETROW[entries];

                // Cycle through the entries.
                for (int index = 0; index < entries; index++)
                {
                    // Call PtrToStructure, getting the structure information.
                    table[index] = (MIB_IPNETROW)Marshal.PtrToStructure(new
                       IntPtr(currentBuffer.ToInt64() + (index *
                       Marshal.SizeOf(typeof(MIB_IPNETROW)))), typeof(MIB_IPNETROW));
                }

                for (int index = 0; index < entries; index++)
                {
                    MIB_IPNETROW row = table[index];
                    IPAddress ip = new IPAddress(BitConverter.GetBytes(row.dwAddr));
                    string macAddr = row.mac0.ToString("X2") + '-' +
                        row.mac1.ToString("X2") + '-' +
                        row.mac2.ToString("X2") + '-' +
                        row.mac3.ToString("X2") + '-' +
                        row.mac4.ToString("X2") + '-' +
                        row.mac5.ToString("X2");
                    if (macAddr.ToUpper() == macSearched.ToUpper())
                    {
                        ips.Add(ip.ToString());
                    }
                }
            }
            finally
            {
                // Release the memory.
                FreeMibTable(buffer);
            }
            return ips.ToArray();
        }
    }
}

参考资料: https://stackoverflow.com/a/1148861/3635715