Develop Reference

No GatewayAddresses when looping through NetworkInterfaces on Xamarin.Android

I'm trying to scan the local IP address of a mobile device to ping all other devices in a network and discover local IP addresses.
In the first step I'm retrieving the GatewayAddress of the local NetworkInterface like this:
foreach (NetworkInterface f in NetworkInterface.GetAllNetworkInterfaces())
{
if (f.OperationalStatus == OperationalStatus.Up)
{
foreach (GatewayIPAddressInformation d in f.GetIPProperties().GatewayAddresses)
{
ip = d.Address.ToString();
}
}
}
This works perfectly fine on iOS, however on Android the GatewayAdresses have a count of 0. As far as my research goes there has been bugs with NetworkInterfaces in Xamarin but they seem to be all fixed by now.

You could use the code to get the ipv6 and ipv4.
foreach (NetworkInterface f in NetworkInterface.GetAllNetworkInterfaces())
{
if (f.OperationalStatus == OperationalStatus.Up)
{
//foreach (GatewayIPAddressInformation d in f.GetIPProperties().GatewayAddresses)
//{
// var ip = d.Address.ToString();
//}
IPAddress ipv6Address = f.GetIPProperties().UnicastAddresses[0].Address; //This will give ipv6 address of certain adapter
IPAddress ipv4Address = f.GetIPProperties().UnicastAddresses[1].Address; //This will give ipv4 address of certain adapter
}
}

Getting Wireless IP address Simply in C# [duplicate]

This question already has answers here:
How do I get the network interface and its right IPv4 address?
(4 answers)
Closed 2 years ago.
So I am having issues gettign someting as simple as the Wireless adapter IP address in C#. I don't feel that it should be this difficult. The PC I am ussing is only WiFi currently so running the below code only returns localhost as an IP address. Looks Like I am only looking at the ethernet interface and not wireless.
Please help.
public static string GetIPAddress()
{
IPHostEntry host;
string localIP = "?";
host = Dns.GetHostEntry(Dns.GetHostName());
foreach (IPAddress ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
localIP = ip.ToString();
}
}
return localIP;
}

This should do the trick. You can either remove or let the NetworkInterfacetype == Network.
foreach(NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())
{
if(ni.NetworkInterfaceType == NetworkInterfaceType.Wireless80211 || ni.NetworkInterfaceType == NetworkInterfaceType.Ethernet)
{
Console.WriteLine(ni.Name);
foreach (UnicastIPAddressInformation ip in ni.GetIPProperties().UnicastAddresses)
{
if (ip.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
{
Console.WriteLine(ip.Address.ToString());
}
}
}
}
credits go to #bwall --> How do I get the network interface and its right IPv4 address?

How to get static IP address information of wireless (media disconnected) preferred network

Currently I am getting the IP address, subnet and default gateway of my interface device ('Wireless Network Connection'). This works fine when the interface has connection, however, when there is no connection, these values no longer output despite still being set statically on the interface device and retrievable using netsh interface ip show address "Wireless Network Connection"
Preferably I would like to avoid having to use netsh in order to parse string to get these values in the case of no connectivity. Is there any way to get these static values on a Wireless interface that does not have a connection?
NetworkInterface[] adapters = NetworkInterface.GetAllNetworkInterfaces();
foreach (NetworkInterface f in adapters)
{
if (f.NetworkInterfaceType != NetworkInterfaceType.Loopback
&& f.NetworkInterfaceType != NetworkInterfaceType.Tunnel
&& f.Name == "Wireless Network Connection")
{
IPInterfaceProperties ipInterface = f.GetIPProperties();
foreach (UnicastIPAddressInformation unicastAddress in ipInterface.UnicastAddresses)
{
textBox1.Text = unicastAddress.Address.ToString();
textBox2.Text = unicastAddress.IPv4Mask.ToString();
}
foreach (GatewayIPAddressInformation d in f.GetIPProperties().GatewayAddresses)
{
textBox3.Text = (d.Address.ToString());
}
}
}

C# get IP information

I want to get the IP Information from my PC.
I can get the Description of the NIC, the IP address and the Subnet Mask, here is my code:
foreach (NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())
{
if (ni.NetworkInterfaceType == NetworkInterfaceType.Wireless80211 || ni.NetworkInterfaceType == NetworkInterfaceType.Ethernet)
{
foreach (UnicastIPAddressInformation ip in ni.GetIPProperties().UnicastAddresses)
{
if (ip.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
{
Nics.Add(ni.Description);
IPs.Add(ip.Address.ToString());
SubnetMasks.Add(ip.IPv4Mask.ToString());
}
}
}
}
so first of all, this shows me some strange NIC's that i don't even see when I type in "ipconfig /all" and things like that the bluetooth gets an IP Adress.
Is there a way that I just get the one that has a connection? And get the Default Gateway?
EDIT:
"Nics", "IPs" and "SubnetMasks" are ArrayLists.
EDIT2:
I used this code:
string asdf = "";
IPHostEntry host;
host = Dns.GetHostEntry(Dns.GetHostName());
foreach (IPAddress ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
MessageBox.Show(ip.ToString());
asdf = ip.ToString();
}
}
textBox1.Text = asdf;
But the Problem is, that I have VMWare and some other NICS that have IP Adresses and the MessageBox shows me all the ip adresses - is it ALWAYS, that the used one is the last? I mean, what if I use this code on another PC and there the used IP Address is not the last in host.AddressList, then it will display the wrong IP Adress.

Get local IP address

In the internet there are several places that show you how to get an IP address. And a lot of them look like this example:
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();
With this example I get several IP addresses, but I'm only interested in getting the one that the router assigns to the computer running the program: the IP that I would give to someone if he wishes to access a shared folder in my computer for instance.
If I am not connected to a network and I am connected to the internet directly via a modem with no router then I would like to get an error. How can I see if my computer is connected to a network with C# and if it is then to get the LAN IP address.

To get local Ip Address:
public static string GetLocalIPAddress()
{
var host = Dns.GetHostEntry(Dns.GetHostName());
foreach (var ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
return ip.ToString();
}
}
throw new Exception("No network adapters with an IPv4 address in the system!");
}
To check if you're connected or not:
System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable();

There is a more accurate way when there are multi ip addresses available on local machine. Connect a UDP socket and read its local endpoint:
string localIP;
using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, 0))
{
socket.Connect("8.8.8.8", 65530);
IPEndPoint endPoint = socket.LocalEndPoint as IPEndPoint;
localIP = endPoint.Address.ToString();
}
Connect on a UDP socket has the following effect: it sets the destination for Send/Recv, discards all packets from other addresses, and - which is what we use - transfers the socket into "connected" state, settings its appropriate fields. This includes checking the existence of the route to the destination according to the system's routing table and setting the local endpoint accordingly. The last part seems to be undocumented officially but it looks like an integral trait of Berkeley sockets API (a side effect of UDP "connected" state) that works reliably in both Windows and Linux across versions and distributions.
So, this method will give the local address that would be used to connect to the specified remote host. There is no real connection established, hence the specified remote ip can be unreachable.

I know this may be kicking a dead horse, but maybe this can help someone. I have looked all over the place for a way to find my local IP address, but everywhere I find it says to use:
Dns.GetHostEntry(Dns.GetHostName());
I don't like this at all because it just gets all the addresses assigned to your computer. If you have multiple network interfaces (which pretty much all computers do now-a-days) you have no idea which address goes with which network interface. After doing a bunch of research I created a function to use the NetworkInterface class and yank the information out of it. This way I can tell what type of interface it is (Ethernet, wireless, loopback, tunnel, etc.), whether it is active or not, and SOOO much more.
public string GetLocalIPv4(NetworkInterfaceType _type)
{
string output = "";
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;
}
Now to get the IPv4 address of your Ethernet network interface call:
GetLocalIPv4(NetworkInterfaceType.Ethernet);
Or your Wireless interface:
GetLocalIPv4(NetworkInterfaceType.Wireless80211);
If you try to get an IPv4 address for a wireless interface, but your computer doesn't have a wireless card installed it will just return an empty string. Same thing with the Ethernet interface.
EDIT:
It was pointed out (thanks #NasBanov) that even though this function goes about extracting the IP address in a much better way than using Dns.GetHostEntry(Dns.GetHostName()) it doesn't do very well at supporting multiple interfaces of the same type or multiple IP addresses on a single interface. It will only return a single IP address when there may be multiple addresses assigned. To return ALL of these assigned addresses you could simply manipulate the original function to always return an array instead of a single string. For example:
public static string[] GetAllLocalIPv4(NetworkInterfaceType _type)
{
List<string> ipAddrList = new List<string>();
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)
{
ipAddrList.Add(ip.Address.ToString());
}
}
}
}
return ipAddrList.ToArray();
}
Now this function will return ALL assigned addresses for a specific interface type. Now to get just a single string, you could use the .FirstOrDefault() extension to return the first item in the array or, if it's empty, return an empty string.
GetLocalIPv4(NetworkInterfaceType.Ethernet).FirstOrDefault();

Refactoring Mrcheif's code to leverage Linq (ie. .Net 3.0+). .
private IPAddress LocalIPAddress()
{
if (!System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable())
{
return null;
}
IPHostEntry host = Dns.GetHostEntry(Dns.GetHostName());
return host
.AddressList
.FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork);
}
:)

Here is a modified version (from compman2408's one) which worked for me:
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;
}
You can call this method for example like:
GetLocalIPv4(NetworkInterfaceType.Ethernet);
The change: I'm retrieving the IP from an adapter which has a gateway IP assigned to it.
Second change: I've added docstrings and break statement to make this method more efficient.

This is the best code I found to get the current IP, avoiding get VMWare host or other invalid IP address.
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()
: "";
}

I think using LINQ is easier:
Dns.GetHostEntry(Dns.GetHostName())
.AddressList
.First(x => x.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
.ToString()

Other way to get IP using linq expression:
public static List<string> GetAllLocalIPv4(NetworkInterfaceType type)
{
return NetworkInterface.GetAllNetworkInterfaces()
.Where(x => x.NetworkInterfaceType == type && x.OperationalStatus == OperationalStatus.Up)
.SelectMany(x => x.GetIPProperties().UnicastAddresses)
.Where(x => x.Address.AddressFamily == AddressFamily.InterNetwork)
.Select(x => x.Address.ToString())
.ToList();
}

For a laugh, thought I'd try and get a single LINQ statement by using the new C# 6 null-conditional operator. Looks pretty crazy and probably horribly inefficient, but it works.
private string GetLocalIPv4(NetworkInterfaceType type = NetworkInterfaceType.Ethernet)
{
// Bastardized from: http://stackoverflow.com/a/28621250/2685650.
return NetworkInterface
.GetAllNetworkInterfaces()
.FirstOrDefault(ni =>
ni.NetworkInterfaceType == type
&& ni.OperationalStatus == OperationalStatus.Up
&& ni.GetIPProperties().GatewayAddresses.FirstOrDefault() != null
&& ni.GetIPProperties().UnicastAddresses.FirstOrDefault(ip => ip.Address.AddressFamily == AddressFamily.InterNetwork) != null
)
?.GetIPProperties()
.UnicastAddresses
.FirstOrDefault(ip => ip.Address.AddressFamily == AddressFamily.InterNetwork)
?.Address
?.ToString()
?? string.Empty;
}
Logic courtesy of Gerardo H (and by reference compman2408).

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;
}

#mrcheif I found this answer today and it was very useful although it did return a wrong IP (not due to the code not working) but it gave the wrong internetwork IP when you have such things as Himachi running.
public static string localIPAddress()
{
IPHostEntry host;
string localIP = "";
host = Dns.GetHostEntry(Dns.GetHostName());
foreach (IPAddress ip in host.AddressList)
{
localIP = ip.ToString();
string[] temp = localIP.Split('.');
if (ip.AddressFamily == AddressFamily.InterNetwork && temp[0] == "192")
{
break;
}
else
{
localIP = null;
}
}
return localIP;
}

Just an updated version of mine using LINQ:
/// <summary>
/// Gets the local Ipv4.
/// </summary>
/// <returns>The local Ipv4.</returns>
/// <param name="networkInterfaceType">Network interface type.</param>
IPAddress GetLocalIPv4(NetworkInterfaceType networkInterfaceType)
{
var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces().Where(i => i.NetworkInterfaceType == networkInterfaceType && i.OperationalStatus == OperationalStatus.Up);
foreach (var networkInterface in networkInterfaces)
{
var adapterProperties = networkInterface.GetIPProperties();
if (adapterProperties.GatewayAddresses.FirstOrDefault() == null)
continue;
foreach (var ip in networkInterface.GetIPProperties().UnicastAddresses)
{
if (ip.Address.AddressFamily != AddressFamily.InterNetwork)
continue;
return ip.Address;
}
}
return null;
}

Pre requisites: you have to add System.Data.Linq reference and refer it
using System.Linq;
string ipAddress ="";
IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
ipAddress = Convert.ToString(ipHostInfo.AddressList.FirstOrDefault(address => address.AddressFamily == AddressFamily.InterNetwork));

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);

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)

Updating Mrchief's answer with Linq, we will have:
public static IPAddress GetLocalIPAddress()
{
var host = Dns.GetHostEntry(Dns.GetHostName());
var ipAddress= host.AddressList.FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork);
return ipAddress;
}

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());
}

string str="";
System.Net.Dns.GetHostName();
IPHostEntry ipEntry = System.Net.Dns.GetHostEntry(str);
IPAddress[] addr = ipEntry.AddressList;
string IP="Your Ip Address Is :->"+ addr[addr.Length - 1].ToString();

Keep in mind, in the general case you could have multiple NAT translations going on, and multiple dns servers, each operating on different NAT translation levels.
What if you have carrier grade NAT, and want to communicate with other customers of the same carrier? In the general case you never know for sure because you might appear with different host names at every NAT translation.

Obsolete gone, this works to me
public static IPAddress GetIPAddress()
{
IPAddress ip = Dns.GetHostAddresses(Dns.GetHostName()).Where(address =>
address.AddressFamily == AddressFamily.InterNetwork).First();
return ip;
}

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()