Get local IP address

Tested with one or multiple LAN cards and Virtual machines

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;
    }

I also was struggling with obtaining the correct IP.

I tried a variety of the solutions here but none provided me the desired affect. Almost all of the conditional tests that was provided caused no address to be used.

This is what worked for me, hope it helps...

var firstAddress = (from address in NetworkInterface.GetAllNetworkInterfaces().Select(x => x.GetIPProperties()).SelectMany(x => x.UnicastAddresses).Select(x => x.Address)
                    where !IPAddress.IsLoopback(address) && address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork
                    select address).FirstOrDefault();

Console.WriteLine(firstAddress);

This returns addresses from any interfaces that have gateway addresses and unicast addresses in two separate lists, IPV4 and IPV6.

public static (List<IPAddress> V4, List<IPAddress> V6) GetLocal()
{
    List<IPAddress> foundV4 = new List<IPAddress>();
    List<IPAddress> foundV6 = new List<IPAddress>();

    NetworkInterface.GetAllNetworkInterfaces().ToList().ForEach(ni =>
    {
        if (ni.GetIPProperties().GatewayAddresses.FirstOrDefault() != null)
        {
            ni.GetIPProperties().UnicastAddresses.ToList().ForEach(ua =>
            {
                if (ua.Address.AddressFamily == AddressFamily.InterNetwork) foundV4.Add(ua.Address);
                if (ua.Address.AddressFamily == AddressFamily.InterNetworkV6) foundV6.Add(ua.Address);
            });
        }
    });

    return (foundV4.Distinct().ToList(), foundV6.Distinct().ToList());
}

Using these:

using System.Net;
using System.Net.Sockets;
using System.Net.NetworkInformation;
using System.Linq;

You can use a series of LINQ methods to grab the most preferred IP address.

public static bool IsIPv4(IPAddress ipa) => ipa.AddressFamily == AddressFamily.InterNetwork;

public static IPAddress GetMainIPv4() => NetworkInterface.GetAllNetworkInterfaces()
.Select((ni)=>ni.GetIPProperties())
.Where((ip)=> ip.GatewayAddresses.Where((ga) => IsIPv4(ga.Address)).Count() > 0)
.FirstOrDefault()?.UnicastAddresses?
.Where((ua) => IsIPv4(ua.Address))?.FirstOrDefault()?.Address;

This simply finds the first Network Interface that has an IPv4 Default Gateway, and gets the first IPv4 address on that interface. Networking stacks are designed to have only one Default Gateway, and therefore the one with a Default Gateway, is the best one.

WARNING: If you have an abnormal setup where the main adapter has more than one IPv4 Address, this will grab only the first one. (The solution to grabbing the best one in that scenario involves grabbing the Gateway IP, and checking to see which Unicast IP is in the same subnet as the Gateway IP Address, which would kill our ability to create a pretty LINQ method based solution, as well as being a LOT more code)

Imports System.Net
Imports System.Net.Sockets
Function LocalIP()
    Dim strHostName = Dns.GetHostName
    Dim Host = Dns.GetHostEntry(strHostName)
    For Each ip In Host.AddressList
        If ip.AddressFamily = AddressFamily.InterNetwork Then
            txtIP.Text = ip.ToString
        End If
    Next

    Return True
End Function

Below same action

Function LocalIP()

   Dim Host As String =Dns.GetHostEntry(Dns.GetHostName).AddressList(1).MapToIPv4.ToString

   txtIP.Text = Host

   Return True

End Function

In addition just simple code for getting Client Ip:

        public static string getclientIP()
        {
            var HostIP = HttpContext.Current != null ? HttpContext.Current.Request.UserHostAddress : "";
            return HostIP;
        }

Hope it's help you.

Modified compman2408's code to be able to iterate through each NetworkInterfaceType.

public static string GetLocalIPv4 (NetworkInterfaceType _type) {
    string output = null;
    foreach (NetworkInterface item in NetworkInterface.GetAllNetworkInterfaces ()) {
        if (item.NetworkInterfaceType == _type && item.OperationalStatus == OperationalStatus.Up) {
            foreach (UnicastIPAddressInformation ip in item.GetIPProperties ().UnicastAddresses) {
                if (ip.Address.AddressFamily == AddressFamily.InterNetwork) {
                    output = ip.Address.ToString ();
                }
            }
        }
    }
    return output;
}

And you can call it like so:

static void Main (string[] args) {
    // Get all possible enum values:
    var nitVals = Enum.GetValues (typeof (NetworkInterfaceType)).Cast<NetworkInterfaceType> ();

    foreach (var nitVal in nitVals) {
        Console.WriteLine ($"{nitVal} => {GetLocalIPv4 (nitVal) ?? "NULL"}");
    }
}

There is already many of answer, but I m still contributing mine one:

public static IPAddress LocalIpAddress() {
    Func<IPAddress, bool> localIpPredicate = ip =>
        ip.AddressFamily == AddressFamily.InterNetwork &&
        ip.ToString().StartsWith("192.168"); //check only for 16-bit block
    return Dns.GetHostEntry(Dns.GetHostName()).AddressList.LastOrDefault(localIpPredicate);
}

One liner:

public static IPAddress LocalIpAddress() => Dns.GetHostEntry(Dns.GetHostName()).AddressList.LastOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork && ip.ToString().StartsWith("192.168"));

note: Search from last because it still worked after some interfaces added into device, such as MobileHotspot,VPN or other fancy virtual adapters.

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

This is the shortest way:

Dns.GetHostEntry(
    Dns.GetHostName()
).AddressList.AsEnumerable().Where(
    ip=>ip.AddressFamily.Equals(AddressFamily.InterNetwork)
).FirstOrDefault().ToString()