Checking static or dynamic IP address in C# .NET?

Checking static or dynamic IP address in C# .NET? - c#

I am building a pretty basic form app.
I can get a list of IP addresses available on the local machine. However, I want to also determine how these addresses are obtained (e.g. DHCP or static). How can I tell if a static IP address is configured on the system?
The goal is to inform a novice end-user (who may have no knowledge of the network setup, or how to obtain it) what static IP addresses are available. And, if no static address exist, inform them that one needs to be setup.
TIA

Better use Net.NetworkInformation due to better performance compared to WMI
using System.Net.NetworkInformation;
NetworkInterface[] niAdpaters = NetworkInterface.GetAllNetworkInterfaces();
private Boolean GetDhcp(Int32 iSelectedAdpater)
{
if (niAdpaters[iSelectedAdpater].GetIPProperties().GetIPv4Properties() != null)
{
return niAdpaters[iSelectedAdpater].GetIPProperties().GetIPv4Properties().IsDhcpEnabled;
}
else
{
return false;
}
}

You can use WMI to get network adapter configuration.
For an example, have a look at http://www.codeproject.com/KB/system/cstcpipwmi.aspx. The 'DhcpEnabled' property on the network adapter should tell you if the address is obtained via dhcp or not.

Unfortunately you'll probably have to use WMI. There might be another way, but this is the only way that I know.
This code will output all of the information about every adapter on your system. I think the name is "DHCPEnabled" of the property you want.
ManagementObjectSearcher searcherNetwork =
new ManagementObjectSearcher("root\\CIMV2",
"SELECT * FROM Win32_NetworkAdapterConfiguration");
foreach (ManagementObject queryObj in searcherNetwork.Get())
{
foreach (var prop in queryObj.Properties)
{
Console.WriteLine(string.Format("Name: {0} Value: {1}", prop.Name, prop.Value));
}
}

I use two method(s) as follows:
public static string GetLocalIPAddress()
{
var host = Dns.GetHostEntry(Dns.GetHostName());
foreach (var ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
return ip.ToString();
}
}
return "unknown";
}
public static string GetLocalIpAllocationMode()
{
string MethodResult = "";
try
{
ManagementObjectSearcher searcherNetwork = new ManagementObjectSearcher("root\\CIMV2", "SELECT * FROM Win32_NetworkAdapterConfiguration");
Dictionary<string, string> Properties = new Dictionary<string, string>();
foreach (ManagementObject queryObj in searcherNetwork.Get())
{
foreach (var prop in queryObj.Properties)
{
if (prop.Name != null && prop.Value != null && !Properties.ContainsKey(prop.Name))
{
Properties.Add(prop.Name, prop.Value.ToString());
}
}
}
MethodResult = Properties["DHCPEnabled"].ToLower() == "true" ? "DHCP" : "Static";
}
catch (Exception ex)
{
ex.HandleException();
}
return MethodResult;
}
GetLocalIpAllocationMode() will tell you whether the ip is static or allocated via dhcp, whereas GetLocalIPAddress() will tell you the local ip itself.

The answers here helped me with my own project, but I had to do some research before I found out how to use the suggested method.
Adding using System.Management; to your code doesn't work by itself. You need to add a reference to System.Management before the namespace will be recognized. (For new people like me who tried this and were getting the error "managementclass could not be found").

Related

Show Preferred DNS and Alternate DNS on a label

I want to be able to show what the current preferred DNS and Alternate DNS is through a label.
How would I do this?
I've looked into it and it seems I have to use
ManagementObjectSearcher? Using WMI?
Something like?
ManagementObjectSearcher mos = new ManagementObjectSearcher("select * from Win32_NetworkAdapter Where AdapterType='DnsForestName'");
foreach (ManagementObject mo in mos.Get())
{
label1.Text = mos.ToString();
}

You may want to look at following - IPInterfaceProperties.DnsAddresses Property
http://msdn.microsoft.com/en-us/library/system.net.networkinformation.ipinterfaceproperties.dnsaddresses(v=vs.110).aspx
The documentation has a nice example of how you can enumerate all network interfaces, and their DNS IP addresses.. but like I said in my comment to your question.. if you have more than one network interface, you have to define criteria for choosing the one you are interested in..
Note that I am not 100% sure that the order in which this property returns DnsAddresses, is primary Dns, followed by 0 or more secondary.. I am guessing that is the case, but there is no documentation that I know of, which will confirm that assumption.

I was able to do what I wanted with this code.
private void Form1_Load(object sender, EventArgs e)
{
NetworkInterface[] adapters = NetworkInterface.GetAllNetworkInterfaces();
foreach (NetworkInterface adapter in adapters)
{
IPInterfaceProperties adapterProperties = adapter.GetIPProperties();
IPAddressCollection dnsServers = adapterProperties.DnsAddresses;
if (dnsServers.Count > 0)
{
Console.WriteLine(adapter.Description);
foreach (IPAddress dns in dnsServers)
{
label4.Text = dns.ToString();
}
}
}
}

Get closest Domain Controller in current AD site without hard coding information

For instances when Active Directory takes too long to replicate data between sites, I need to ensure that the local AD replica contains the most up to date information.
How can I get a list of DomainControllers for the current site?
I haven't found anything on Codeproject or on StackOverflow

Going to all this trouble is probably wasted effort. Unless you are experiencing issues with the built in logic for finding a domain controller you should just go with the built in method that returns one. According to Microsoft it automatically tries to find the closes one: http://technet.microsoft.com/en-us/library/cc978016.aspx.
Just use the static DomainController.FindOne method and pass in your directorycontext.
Update
Alright, try the code below, let me know how it works for you. It pings each, returns the roundtrip time, if -1 (no connection) it skips it. Flags PDC status if present. Orders by PDC status, followed by ping round trip.
static void Main(string[] args)
{
var dcsInOrder = (from DomainController c in Domain.GetCurrentDomain().DomainControllers
let responseTime = Pinger(c.Name)
where responseTime >=0
let pdcStatus = c.Roles.Contains(ActiveDirectoryRole.PdcRole)
orderby pdcStatus, responseTime
select new {DC = c, ResponseTime = responseTime}
).ToList();
foreach (var dc in dcsInOrder)
{
System.Console.WriteLine(dc.DC.Name + " - " + dc.ResponseTime);
}
System.Console.ReadLine();
}
private static int Pinger(string address)
{
Ping p = new Ping();
try
{
PingReply reply = p.Send(address, 3000);
if (reply.Status == IPStatus.Success) return (int)reply.RoundtripTime;
}
catch { }
return -1;
}

First, I'll answer the question that you actually asked:
System.DirectoryServices.ActiveDirectory.ActiveDirectorySite.GetComputerSite().Servers
But it seems like you're asking how to make sure that you're talking to the closest domain controller possible. Windows doesn't exactly provide this functionality, the best it will do is give you a domain controller in the same site that the code is running from.
I think the first thing to check is that you have your sites and subnets configured correctly. Run Active Directory Sites and Services, and make sure that subnets and domain controllers are assigned to the correct sites.
This MSDN page (and the Technet article in Peter's answer) says that you must be searching by the DNS name for the DC Locator to attempt to find a DC in the current site. I don't know if the Name property of the Domain class is the DNS domain name.
I have to assume that DomainController.FindOne is a wrapper for DsGetDcName. At that link, you can find how to turn on tracing for that function. You can use this if you still have problems, or maybe you should just PInvoke this function.

Here is a code sample that has no hard coding of DCs. Comments and criticism are welcome.
/// <summary>
/// For best results ensure all hosts are pingable, and turned on.
/// </summary>
/// <returns>An ordered list of DCs with the PDCE first</returns>
static LinkedList<DomainController> GetNearbyDCs()
{
LinkedList<DomainController> preferredDCs = new LinkedList<DomainController>();
List<string> TestedDCs = new List<string>();
using (var mysite = ActiveDirectorySite.GetComputerSite())
{
using (var currentDomain = Domain.GetCurrentDomain())
{
DirectoryContext dctx = new DirectoryContext(DirectoryContextType.Domain, currentDomain.Name);
var listOfDCs = DomainController.FindAll(dctx, mysite.Name);
foreach (DomainController item in listOfDCs)
{
Console.WriteLine(item.Name );
if (IsConnected(item.IPAddress))
{
// Enumerating "Roles" will cause the object to bind to the server
ActiveDirectoryRoleCollection rollColl = item.Roles;
if (rollColl.Count > 0)
{
foreach (ActiveDirectoryRole roleItem in rollColl)
{
if (!TestedDCs.Contains(item.Name))
{
TestedDCs.Add(item.Name);
if (roleItem == ActiveDirectoryRole.PdcRole)
{
preferredDCs.AddFirst(item);
break;
}
else
{
if (preferredDCs.Count > 0)
{
var tmp = preferredDCs.First;
preferredDCs.AddBefore(tmp, item);
}
else
{
preferredDCs.AddFirst(item);
}
break;
}
}
}
}
else
{
// The DC exists but has no roles
TestedDCs.Add(item.Name);
if (preferredDCs.Count > 0)
{
var tmp = preferredDCs.First;
preferredDCs.AddBefore(tmp, item);
}
else
{
preferredDCs.AddFirst(item);
}
}
}
else
{
preferredDCs.AddLast(item);
}
}
}
}
return preferredDCs;
}
static bool IsConnected(string hostToPing)
{
string pingurl = string.Format("{0}", hostToPing);
string host = pingurl;
bool result = false;
Ping p = new Ping();
try
{
PingReply reply = p.Send(host, 3000);
if (reply.Status == IPStatus.Success)
return true;
}
catch { }
return result;
}

Here's my approach using powershell but I'm sure it's a simple implementation in c#, etc. If DHCP is setup correctly, the Primary DNS server in your subnet should be the closest Domain Controller. So the following code should grab the first DNS IP and resolve it to the hostname of the closest DC. This doesn't require RSAT or credentials and contains no specific properties of the current domain.
$NetItems = #(Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter "IPEnabled = 'True'" -ComputerName $env:COMPUTERNAME)
foreach ($objItem in $NetItems)
{
if ($objItem.{DNSServerSearchOrder}.Count -ge 1)
{
$PrimaryDNS = $objItem.DNSServerSearchOrder[0]
$domain = $objItem.DNSDomain
break
}
}
[System.Net.Dns]::GetHostbyAddress($PrimaryDNS).hostname -replace ".$($domain)",""

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()

Get IP of my machine C# with virtual machine installed

I want to get the current IP address of the computer that has say 3 virtual machines (VM Ware) installed. I want to get LAN address of that computer.
current code that i have returns me an array but how to identify current computer lan address ?
public static string getThisCompIPAddress()
{
IPAddress[] addresslist = Dns.GetHostAddresses(Dns.GetHostName());
return (addresslist[0].ToString());
}
addresslist returns an array of 3 IP addresses

You could try the NetworkInterface class, and try to match the name or physical address of the LAN connection to find out the real one. Maybe searching within this class and it's members you can find something that suits your needs.
Here is a simple method to provide some usage info:
using System.Net.NetworkInformation;
...
static void ViewNetworkInfo()
{
NetworkInterface[] networks = NetworkInterface.GetAllNetworkInterfaces();
foreach (NetworkInterface nw in networks)
{
Console.WriteLine(nw.Name);
Console.WriteLine(nw.GetPhysicalAddress().ToString());
IPInterfaceProperties ipProps = nw.GetIPProperties();
foreach (UnicastIPAddressInformation ucip in ipProps.UnicastAddresses)
{
Console.WriteLine(ucip.Address.ToString());
}
Console.WriteLine();
}
Console.ReadKey();
}

I've tried all of the solutions above but couldn't get the ip from my "real" machine and not the virtual one. I've managed to use this to get the IP from my virtual machine:
IPAddress[] addresslist = Dns.GetHostAddresses(Environment.ExpandEnvironmentVariables("%CLIENTNAME%"));
The reason why I used it this way is that the function Dns.GetHostAddresses return the adresses of the given host, so if you use the Dns.GetHostName() function it will return the virtual-machine name and not the local machine, but using the name of the machine where you can find using the: Environment.ExpandEnvironmentVariables("%CLIENTNAME%") you can get the client name and not the virtual-machine name, this way you can get the real IP of your local machine.
I hope this helps.

public static ArrayList getThisCompIPAddress()
{
ArrayList strArrIpAdrs = new ArrayList();
ArrayList srtIPAdrsToReturn = new ArrayList();
addresslist = Dns.GetHostAddresses(Dns.GetHostName());
for (int i = 0; i < addresslist.Length; i++)
{
try
{
long ip = addresslist[i].Address;
strArrIpAdrs.Add(addresslist[i]);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
foreach (IPAddress ipad in strArrIpAdrs)
{
lastIndexOfDot = ipad.ToString().LastIndexOf('.');
substring = ipad.ToString().Substring(0, ++lastIndexOfDot);
if (!(srtIPAdrsToReturn.Contains(substring)) && !(substring.Equals("")))
{
srtIPAdrsToReturn.Add(substring);
}
}
return srtIPAdrsToReturn;
}
this is 100% working, the real problem was that it was throwing error while calculating Address that returns long. Error Code is 10045

How to get bluetooth mac address from local pc?

I want to get the mac address of the bluetooth device on the pc my application is running on.
I have tried the following:
private void GetMacAddress()
{
string macAddresses = "";
foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces())
{
if (nic.OperationalStatus == OperationalStatus.Up)
{
macAddresses += nic.GetPhysicalAddress().ToString();
Console.WriteLine(macAddresses);
}
}
}
But the output does not match with 'ipconfig /all' in commandprompt. It does not print my blueotths mac address.
Any solutions?
I am ready to parse the output I get from 'ipconfig /all' but how do I get the output as a String?

public static PhysicalAddress GetBTMacAddress() {
foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces()) {
// Only consider Bluetooth network interfaces
if (nic.NetworkInterfaceType != NetworkInterfaceType.FastEthernetFx &&
nic.NetworkInterfaceType != NetworkInterfaceType.Wireless80211){
return nic.GetPhysicalAddress();
}
}
return null;
}

You can maybe use WMI to get the results. Herewith a link to a WMI solution that trails through the network devices.
I'm posting the code here in case the website is down, but all credit goes to the original author, PsychoCoder.
Use WMI to get MAC Address in C#
And the code:
//Namespace reference
using System.Management;
/// <summary>
/// Returns MAC Address from first Network Card in Computer
/// </summary>
/// <returns>MAC Address in string format</returns>
public string FindMACAddress()
{
//create out management class object using the
//Win32_NetworkAdapterConfiguration class to get the attributes
//af the network adapter
ManagementClass mgmt = new ManagementClass("Win32_NetworkAdapterConfiguration");
//create our ManagementObjectCollection to get the attributes with
ManagementObjectCollection objCol = mgmt.GetInstances();
string address = String.Empty;
//My modification to the code
var description = String.Empty;
//loop through all the objects we find
foreach (ManagementObject obj in objCol)
{
if (address == String.Empty) // only return MAC Address from first card
{
//grab the value from the first network adapter we find
//you can change the string to an array and get all
//network adapters found as well
if ((bool)obj["IPEnabled"] == true)
{
address = obj["MacAddress"].ToString();
description = obj["Description"].ToString();
}
}
//dispose of our object
obj.Dispose();
}
//replace the ":" with an empty space, this could also
//be removed if you wish
address = address.Replace(":", "");
//return the mac address
return address;
}
Be sure to include the reference to System.Management.
In order for you to get the network device name, you can use the obj["Description"].ToString();
You can also have a look at MSDN regarding WMI, specifically to the Win32_NetworkAdapterConfiguration Class
Hope this helps.

Develop Reference

C# (C-Sharp) is a programming language developed by Microsoft that runs on the .NET Framework.

Checking static or dynamic IP address in C# .NET? - c#

You can use WMI to get network adapter configuration. For an example, have a look at http://www.codeproject.com/KB/system/cstcpipwmi.aspx. The 'DhcpEnabled' property on the network adapter should tell you if the address is obtained via dhcp or not.

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