获取本地IP地址

在互联网上有几个地方告诉你如何获得一个IP地址。很多都像这个例子:

String strHostName = string.Empty;
// Getting Ip address of local machine...
// First get the host name of local machine.
strHostName = Dns.GetHostName();
Console.WriteLine("Local Machine's Host Name: " + strHostName);
// Then using host name, get the IP address list..
IPHostEntry ipEntry = Dns.GetHostEntry(strHostName);
IPAddress[] addr = ipEntry.AddressList;

for (int i = 0; i < addr.Length; i++)
{
    Console.WriteLine("IP Address {0}: {1} ", i, addr[i].ToString());
}
Console.ReadLine();

在这个例子中，我得到了几个IP地址，但我只对路由器分配给运行程序的计算机的IP地址感兴趣:例如，如果某人希望访问我计算机中的共享文件夹，我将给他的IP地址。

如果我没有连接到网络，我直接通过没有路由器的调制解调器连接到互联网，那么我希望得到一个错误。我如何才能看到我的计算机是否连接到网络与c#，如果它是然后得到局域网IP地址。

当前回答

请记住，在一般情况下，您可能有多个正在进行的NAT转换，以及多个dns服务器，每个服务器都运行在不同的NAT转换级别上。

如果您有运营商级NAT，并且想与同一运营商的其他客户通信，该怎么办?在一般情况下，您永远无法确定，因为在每次NAT转换时可能会出现不同的主机名。

2015-07-01 11:25:26

其他回答

使用一个或多个LAN卡和虚拟机进行测试

public static string DisplayIPAddresses()
    {
        string returnAddress = String.Empty;

        // Get a list of all network interfaces (usually one per network card, dialup, and VPN connection)
        NetworkInterface[] networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();

        foreach (NetworkInterface network in networkInterfaces)
        {
            // Read the IP configuration for each network
            IPInterfaceProperties properties = network.GetIPProperties();

            if (network.NetworkInterfaceType == NetworkInterfaceType.Ethernet &&
                   network.OperationalStatus == OperationalStatus.Up &&
                   !network.Description.ToLower().Contains("virtual") &&
                   !network.Description.ToLower().Contains("pseudo"))
            {
                // Each network interface may have multiple IP addresses
                foreach (IPAddressInformation address in properties.UnicastAddresses)
                {
                    // We're only interested in IPv4 addresses for now
                    if (address.Address.AddressFamily != AddressFamily.InterNetwork)
                        continue;

                    // Ignore loopback addresses (e.g., 127.0.0.1)
                    if (IPAddress.IsLoopback(address.Address))
                        continue;

                    returnAddress = address.Address.ToString();
                    Console.WriteLine(address.Address.ToString() + " (" + network.Name + " - " + network.Description + ")");
                }
            }
        }

       return returnAddress;
    }

2018-10-05 05:05:19

用Linq更新Mrchief的答案，我们会有:

public static IPAddress GetLocalIPAddress()
{
   var host = Dns.GetHostEntry(Dns.GetHostName());
   var ipAddress= host.AddressList.FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork);
   return ipAddress;
}

2018-02-26 08:39:27

这是我发现的最好的代码，以获得当前的IP，避免获得VMWare主机或其他无效的IP地址。

public string GetLocalIpAddress()
{
    UnicastIPAddressInformation mostSuitableIp = null;

    var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();

    foreach (var network in networkInterfaces)
    {
        if (network.OperationalStatus != OperationalStatus.Up)
            continue;

        var properties = network.GetIPProperties();

        if (properties.GatewayAddresses.Count == 0)
            continue;

        foreach (var address in properties.UnicastAddresses)
        {
            if (address.Address.AddressFamily != AddressFamily.InterNetwork)
                continue;

            if (IPAddress.IsLoopback(address.Address))
                continue;

            if (!address.IsDnsEligible)
            {
                if (mostSuitableIp == null)
                    mostSuitableIp = address;
                continue;
            }

            // The best IP is the IP got from DHCP server
            if (address.PrefixOrigin != PrefixOrigin.Dhcp)
            {
                if (mostSuitableIp == null || !mostSuitableIp.IsDnsEligible)
                    mostSuitableIp = address;
                continue;
            }

            return address.Address.ToString();
        }
    }

    return mostSuitableIp != null 
        ? mostSuitableIp.Address.ToString()
        : "";
}

2016-11-10 13:27:36

Dns.GetHostEntry(Dns.GetHostName()).AddressList[1].MapToIPv4() //returns 192.168.14.1

2020-03-08 09:32:17

下面是一个修改后的版本(来自compman2408的版本)，它对我来说很有效:

    internal static string GetLocalIPv4(NetworkInterfaceType _type)
    {  // Checks your IP adress from the local network connected to a gateway. This to avoid issues with double network cards
        string output = "";  // default output
        foreach (NetworkInterface item in NetworkInterface.GetAllNetworkInterfaces()) // Iterate over each network interface
        {  // Find the network interface which has been provided in the arguments, break the loop if found
            if (item.NetworkInterfaceType == _type && item.OperationalStatus == OperationalStatus.Up)
            {   // Fetch the properties of this adapter
                IPInterfaceProperties adapterProperties = item.GetIPProperties();
                // Check if the gateway adress exist, if not its most likley a virtual network or smth
                if (adapterProperties.GatewayAddresses.FirstOrDefault() != null)
                {   // Iterate over each available unicast adresses
                    foreach (UnicastIPAddressInformation ip in adapterProperties.UnicastAddresses)
                    {   // If the IP is a local IPv4 adress
                        if (ip.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
                        {   // we got a match!
                            output = ip.Address.ToString();
                            break;  // break the loop!!
                        }
                    }
                }
            }
            // Check if we got a result if so break this method
            if (output != "") { break; }
        }
        // Return results
        return output;
    }

你可以像这样调用这个方法:

GetLocalIPv4(NetworkInterfaceType.Ethernet);

变化:我正在从一个适配器中检索IP，该适配器已分配了一个网关IP。第二个变化:我添加了文档字符串和break语句，以使该方法更有效。

2015-02-20 03:39:00

获取本地IP地址

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