Wake on LAN using C# - c#

What's the best way going forward to implement Wake on LAN using C#?
The functionality is needed for machines in a LAN environment (and not over the internet). The method needs to be robust enough to take care of firewalls and other such issues. Also, for systems not supporting this functionality, or having it disabled, is there an alternative?
The primary objective - wake up machines (from shutdown/hibernate state) over the LAN - this is to be programmed using C#.
Please guide.
PS: I've come across the following:
http://blog.memos.cz/index.php/team/2008/06/12/wake-on-lan-in-csharp
http://community.bartdesmet.net/blogs/bart/archive/2006/04/02/3858.aspx
http://www.codeproject.com/KB/IP/cswol.aspx
However, I'm new to this and hence couldn't figure if the solutions were comprehensive enough. If someone could recommend following either of the above articles, that'd help.

Very old question, I know, but still valid. Since I didn't see any C# in the accepted answer, I wrote my own 'Wake On Lan' code.
My goal was to make a universal and easy Wake On Lan class that:
works with ipv4, ipv6 and dual-stack.
works with one or multiple network cards (NICS) connected to different networks (both computers).
works with macaddress in any standard hex format.
works using multicast (broadcast is buggy in Windows when using multiple NICs and is not supported when using ipv6).
How to use:
All you need, is the MAC address of the wired nic on the computer you wish to wake up. Any standard hex representation will do. Then call the code like this:
string mac = "01-02-03-04-05-06";
await WOL.WakeOnLan(mac);
Here's the class:
using System;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
public static class WOL
{
public static async Task WakeOnLan(string macAddress)
{
byte[] magicPacket = BuildMagicPacket(macAddress);
foreach (NetworkInterface networkInterface in NetworkInterface.GetAllNetworkInterfaces().Where((n) =>
n.NetworkInterfaceType != NetworkInterfaceType.Loopback && n.OperationalStatus == OperationalStatus.Up))
{
IPInterfaceProperties iPInterfaceProperties = networkInterface.GetIPProperties();
foreach (MulticastIPAddressInformation multicastIPAddressInformation in iPInterfaceProperties.MulticastAddresses)
{
IPAddress multicastIpAddress = multicastIPAddressInformation.Address;
if (multicastIpAddress.ToString().StartsWith("ff02::1%", StringComparison.OrdinalIgnoreCase)) // Ipv6: All hosts on LAN (with zone index)
{
UnicastIPAddressInformation unicastIPAddressInformation = iPInterfaceProperties.UnicastAddresses.Where((u) =>
u.Address.AddressFamily == AddressFamily.InterNetworkV6 && !u.Address.IsIPv6LinkLocal).FirstOrDefault();
if (unicastIPAddressInformation != null)
{
await SendWakeOnLan(unicastIPAddressInformation.Address, multicastIpAddress, magicPacket);
break;
}
}
else if (multicastIpAddress.ToString().Equals("224.0.0.1")) // Ipv4: All hosts on LAN
{
UnicastIPAddressInformation unicastIPAddressInformation = iPInterfaceProperties.UnicastAddresses.Where((u) =>
u.Address.AddressFamily == AddressFamily.InterNetwork && !iPInterfaceProperties.GetIPv4Properties().IsAutomaticPrivateAddressingActive).FirstOrDefault();
if (unicastIPAddressInformation != null)
{
await SendWakeOnLan(unicastIPAddressInformation.Address, multicastIpAddress, magicPacket);
break;
}
}
}
}
}
static byte[] BuildMagicPacket(string macAddress) // MacAddress in any standard HEX format
{
macAddress = Regex.Replace(macAddress, "[: -]", "");
byte[] macBytes = new byte[6];
for (int i = 0; i < 6; i++)
{
macBytes[i] = Convert.ToByte(macAddress.Substring(i * 2, 2), 16);
}
using (MemoryStream ms = new MemoryStream())
{
using (BinaryWriter bw = new BinaryWriter(ms))
{
for (int i = 0; i < 6; i++) //First 6 times 0xff
{
bw.Write((byte)0xff);
}
for (int i = 0; i < 16; i++) // then 16 times MacAddress
{
bw.Write(macBytes);
}
}
return ms.ToArray(); // 102 bytes magic packet
}
}
static async Task SendWakeOnLan(IPAddress localIpAddress, IPAddress multicastIpAddress, byte[] magicPacket)
{
using (UdpClient client = new UdpClient(new IPEndPoint(localIpAddress, 0)))
{
await client.SendAsync(magicPacket, magicPacket.Length, multicastIpAddress.ToString(), 9);
}
}
}
How it works:
The code works by enumerating all network cards that are 'up' and connected to your network (that's usually just one). It will send out the 'magic packet' to all your connected networks using multicast, which works with both ipv4 and ipv6 (don't worry about flooding your network, it's only 102 bytes).
To work, the computer, you want to wake up, must have a wired connection (wireless computers can't be woken up, since they aren't connected to any network, when they are off). The computer, that sends the packet, can be wireless connected.
Firewalls are usually no problem, since the computer is off and hence the firewall is not active.
You must make sure that 'Wake on lan' is enabled in the computer's BIOS and on the network card.
Update for .Net 6 (and a bug fix):
Fixed a bug, where if Ipv6 was functioning on the computer that sends the packet but not on the one, that should be awakened, then it would not try Ipv4 (this is fixed in the code above).
Here's the code that works on .Net 6 (borrowed some of #Oskar Sjôberg's code) - implicit usings turned on:
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;
using System.Text.RegularExpressions;
public static class WOL
{
public static async Task WakeOnLan(string macAddress)
{
byte[] magicPacket = BuildMagicPacket(macAddress);
foreach (NetworkInterface networkInterface in NetworkInterface.GetAllNetworkInterfaces().Where((n) =>
n.NetworkInterfaceType != NetworkInterfaceType.Loopback && n.OperationalStatus == OperationalStatus.Up))
{
IPInterfaceProperties iPInterfaceProperties = networkInterface.GetIPProperties();
foreach (MulticastIPAddressInformation multicastIPAddressInformation in iPInterfaceProperties.MulticastAddresses)
{
IPAddress multicastIpAddress = multicastIPAddressInformation.Address;
if (multicastIpAddress.ToString().StartsWith("ff02::1%", StringComparison.OrdinalIgnoreCase)) // Ipv6: All hosts on LAN (with zone index)
{
UnicastIPAddressInformation? unicastIPAddressInformation = iPInterfaceProperties.UnicastAddresses.Where((u) =>
u.Address.AddressFamily == AddressFamily.InterNetworkV6 && !u.Address.IsIPv6LinkLocal).FirstOrDefault();
if (unicastIPAddressInformation != null)
{
await SendWakeOnLan(unicastIPAddressInformation.Address, multicastIpAddress, magicPacket);
}
}
else if (multicastIpAddress.ToString().Equals("224.0.0.1")) // Ipv4: All hosts on LAN
{
UnicastIPAddressInformation? unicastIPAddressInformation = iPInterfaceProperties.UnicastAddresses.Where((u) =>
u.Address.AddressFamily == AddressFamily.InterNetwork && !iPInterfaceProperties.GetIPv4Properties().IsAutomaticPrivateAddressingActive).FirstOrDefault();
if (unicastIPAddressInformation != null)
{
await SendWakeOnLan(unicastIPAddressInformation.Address, multicastIpAddress, magicPacket);
}
}
}
}
}
static byte[] BuildMagicPacket(string macAddress) // MacAddress in any standard HEX format
{
macAddress = Regex.Replace(macAddress, "[: -]", "");
byte[] macBytes = Convert.FromHexString(macAddress);
IEnumerable<byte> header = Enumerable.Repeat((byte)0xff, 6); //First 6 times 0xff
IEnumerable<byte> data = Enumerable.Repeat(macBytes, 16).SelectMany(m => m); // then 16 times MacAddress
return header.Concat(data).ToArray();
}
static async Task SendWakeOnLan(IPAddress localIpAddress, IPAddress multicastIpAddress, byte[] magicPacket)
{
using UdpClient client = new(new IPEndPoint(localIpAddress, 0));
await client.SendAsync(magicPacket, magicPacket.Length, new IPEndPoint(multicastIpAddress, 9));
}
}

For the WOL problem you have to clarify three problems to get it to work:
Send a WOL over the ethernet cable
Configure your PC to listen for such
a packet and wake up
Make sure the packet will come from
sender to receiver (firewall,
gateways, etc.)
As you already found on the net there are existing several solutions for the first problem programmed in C# (and after skimming your links, I would start with the first one).
The second one is something you can only achieve by configuring your network adapter. Just open the device manager and take a look into the properties of your network adapter, if such an option exists and if you can enable it. This can't be programmed, due to the fact that every network adapter has another implementation of that function and how it can be enabled.
The third problem can't also be solved by C#. It is a pure network problem, where you have to configure your router, gateways, ids-systems, etc. to allow such a packet and let it flow from sender to receiver. Due to the fact, that a WOL packet is always a broadcast packet (dest-ip 255.255.255.255) it won't leave your local network and will always be dropped from router, gateways or any other bridge between to networks (e.g. vpns, etc.).
Last but not least, I will just remind you, that the first problem can be divided into some smaller packets but as far as I could see these problems are all capped by the links you provided.

I was trying Poul Bak´s answer but was unable to wake my target computer. After verifying that a third party application, WakeMeOnLan in fact was able to wake my target computer, I wrote this code that worked for me:
void SendWakeOnLan(PhysicalAddress target)
{
var header = Enumerable.Repeat(byte.MaxValue, 6);
var data = Enumerable.Repeat(target.GetAddressBytes(), 16).SelectMany(mac => mac);
var magicPacket = header.Concat(data).ToArray();
using var client = new UdpClient();
client.Send(magicPacket, magicPacket.Length, new IPEndPoint(IPAddress.Broadcast, 9));
}
Usage:
Simply by passing in the target computers mac address like so:
SendWakeOnLan(PhysicalAddress.Parse("0A-0B-0C-0D-0E-0F"));
I think the main difference between this answer and Poul Bak´s answer is that this code is using broadcast over IPv4 instead of multicast on IPv4/IPv6, and maybe my network equipment is not handling/setup to do multicast correctly.

Related

How to enumerate devices on a network from c# and .NET?

I am writing a Windows desktop app that communicates with my DSLR camera via Wireless network (WLAN). I need a way to scan the network and find the camera by its MAC address or other identifying information. Nirsoft Wireless Network Watcher displays information about each device on my network. (Specifically: 'IP Address', 'Device Name', 'MAC Address', 'Network Adapter Company', etc.) Does .NET provide a way to retrieve this information from C#?
You can check out the following blog where someone already wrote a code for something like this.
https://www.maniuk.net/2016/08/get-ip-address-by-mac-address-in-csharp.html
This uses the command line arp command as an external process. I have tested it and seems to be working ok. As the code stands the mac address has to be in the format aa-bb-cc-dd-ee-ff
Alternatively, there is a Nuget Package called ArpLookup.
https://www.nuget.org/packages/ArpLookup/
With this one, you have to provide the IP Address and it will return the mac address. So you would have to enumerate through your IP range and return the one that matches the mac address.
Something like this:
private static async Task<string> GetIPFromMAC(string macAddress)
{
var ping = new Ping();
var start = BitConverter.ToInt32(new byte[] { 1, 0, 168, 192 }, 0);
var end = BitConverter.ToInt32(new byte[] { 254, 0, 168, 192 }, 0);
for (var i = start; i <= end; i++)
{
var bytes = BitConverter.GetBytes(i);
var ipAddress = new IPAddress(new[] {bytes[3], bytes[2], bytes[1], bytes[0]});
var reply = ping.Send(ipAddress, 200);
if (reply == null || reply.Status == IPStatus.TimedOut) continue;
var mac = await Arp.LookupAsync(ipAddress);
if (macAddress == mac.ToString()) return ipAddress.ToString();
}
return string.Empty;
}
You need to replace the values in start and end with your IP range and then you can call the code like this.
var ip = GetIPFromMAC("aabbccddeeff").Result;

Unable to read from Serial Port using C# Mono (RaspberryPi)

I'm attempting to write a C# library which looks at all available USB serial ports on a Raspberry Pi so that I can enumerate, identify and communicate with a set of Arduinos connected to the Pi via a USB hub.
I am able to make this work on my windows machine (several Arduinos connected to my desktop computer) and have even been able to make it work on my Pi however, I am struggling to understand how to generalize the fix.
If I attempt to run the program by itself on the Pi, I am able to open the serial port and send data however, I cannot receive anything from the Arduinos: I get timeout exceptions. I understand that Mono's implementation of SerialPort is limited and I must use SerialPort.ReadByte() instead of Readline() and the data received events (my solution is based on code from HowToSystemIOPorts). My Serial port enumeration is using a method outlined in another stack exchange response here.
My timeout is currently set to 4 seconds, which is several orders of magnitude longer than I expect to receive the message.
After a lot of googling, I came across mention of using minicom to initialize the serial port here, which to my surprise allowed me to receive data from the Arduino. The biggest drawback is that I need to initialize the port using minicom and leave the process opening each time I boot the Pi. I also can't seem to figure out how to make this work with multiple Arduinos.
Here is what I have tried so far:
Updated the Pi firmware and software to their latest versions
Attempted to use both an Arduino MEGA 2560 R3 and Arduino UNO
Changed the owner of the tty* ports (ttyACM0 and ttyUSB0 in this case) to both my user and group
Successfully configured the port via minicom, left the process running and start the program and read/wrote data. A manual process which only seems to work for one Arduino at a time
Successfully run the program in Windows without fault
Verified the Arduinos are recognized by the Pi running "dmesg | grep tty"
Here is what I hope to solve:
Automatic setup/initialization of the Arduino serial ports. Whether through a shell script run before the main program or within Mono code so that the code below can run as intended.
Here is my connection code:
public bool StartArduinoComms()
{
string[] ports = GetPortNames();
foreach (string port in ports)
{
mLogger.LogMessage(ProsthesisCore.Utility.Logger.LoggerChannels.Arduino, string.Format("Found serial port {0}", port));
}
bool foundCorrectArduino = false;
var idPacket = new ArduinoMessageBase();
idPacket.ID = ArduinoMessageValues.kIdentifyValue;
string jsonOutput = Newtonsoft.Json.JsonConvert.SerializeObject(idPacket);
foreach (string port in ports)
{
SerialPort serialPort = new SerialPort(port, kArduinoCommsBaudRate);
serialPort.Parity = Parity.None;
serialPort.DataBits = 8;
serialPort.StopBits = StopBits.One;
//Only check unopened ports
if (!serialPort.IsOpen)
{
serialPort.Open();
//Disable telemtry just incase
var toggle = new { ID = ArduinoMessageValues.kTelemetryEnableValue, EN = false };
string disableTelem = Newtonsoft.Json.JsonConvert.SerializeObject(toggle);
serialPort.Write(disableTelem);
//Discard any built up data
serialPort.DiscardInBuffer();
serialPort.Write(jsonOutput);
serialPort.ReadTimeout = kIDTimeoutMilliseconds;
string response = string.Empty;
for (int i = 0; i < kNumRetries; ++i)
{
try
{
//This is guaranteed to timeout if not configured through minicom
response = ReadLine(serialPort);
break;
}
//Catch case where the serial port is unavailable. MOve to next port
catch (TimeoutException)
{
continue;
}
}
if (!string.IsNullOrEmpty(response))
{
//Perform response validation
}
else
{
//Got no response
}
if (!foundCorrectArduino)
{
serialPort.Close();
}
}
}
return foundCorrectArduino;
}
/// <summary>
/// From https://stackoverflow.com/questions/434494/serial-port-rs232-in-mono-for-multiple-platforms
/// </summary>
/// <returns></returns>
private static string[] GetPortNames()
{
int p = (int)Environment.OSVersion.Platform;
List<string> serial_ports = new List<string>();
// Are we on Unix?
if (p == 4 || p == 128 || p == 6)
{
string[] ttys = System.IO.Directory.GetFiles("/dev/", "tty*");
foreach (string dev in ttys)
{
//Arduino MEGAs show up as ttyACM due to their different USB<->RS232 chips
if (dev.StartsWith("/dev/ttyS") || dev.StartsWith("/dev/ttyUSB") || dev.StartsWith("/dev/ttyACM"))
{
serial_ports.Add(dev);
}
}
}
else
{
serial_ports.AddRange(SerialPort.GetPortNames());
}
return serial_ports.ToArray();
}
Have a look at stty command. It will let you set/read teminal settings
http://linux.about.com/od/lna_guide/a/gdelna38t01.htm will give a rundown on it's use.
It would be easier to call out to than minicom, and the settings stay on the device.
I have done something like the same as you before.
I had to read and write data through USB Serial adapter, and didnt use minicom.
It may not be god code but i found that inorder to read the data I could create a new thread and have that check for data, my code include a lot of stuff but basicly i did this:
System.Threading.Thread newThread;
newThread = new System.Threading.Thread(this.check_get_data);
and the check_get_data method
public void check_get_data ()
{
byte tmpByte = 0;
while (m_objSerialPort.BytesToRead != 0) {
tmpByte = (byte)m_objSerialPort.ReadByte ();
DoSomethingWithByte(tmpByte);
Thread.Sleep(20);
}
}
this is currently running with two usbserials. dont know if it helps but hope you find your solution

Check if IP is in LAN (behind firewalls and routers)

I've been crawling in the web for about 5 hours now and couldn't find a solution for my problem:
My company is developing an educational game and I'm writing an autoupdater for it using Monotorrent. The game will be used in schools, but because most schools only have very weak internet connections there should only be one computer in the network that downloads from a httpseeder, and the others should leech from the one computer that is downloading from the httpseed.
So I get loads of IP-addresses from the tracker and need to filter out only the ones that are in the LAN.
Of course schools are sometimes quite strict with firewalls and there will be loads of routers and switches between some computers in a school.
I've already tried most solutions, things like
NetworkInterface[] interfaces = NetworkInterface.GetAllNetworkInterfaces();
foreach (NetworkInterface iface in interfaces)
{
IPInterfaceProperties properties = iface.GetIPProperties();
foreach (UnicastIPAddressInformation address in properties.UnicastAddresses)
{
Console.WriteLine(
"{0} (Mask: {1})",
address.Address,
address.IPv4Mask
);
}
}
Or similar techniques only deliver the information of the router/switch/whatever.
So in a nutshell, what I want to do is check if a given IP is accessible via LAN.
I'd really appreciate any help because this feature is the last one remaining :)
You could take advantage of TTL. With a TTL of 1 the packet won't be able to make it to the internet:
private static bool IsLanIP(IPAddress address)
{
var ping = new Ping();
var rep = ping.Send(address, 100, new byte[] { 1 }, new PingOptions()
{
DontFragment = true,
Ttl = 1
});
return rep.Status != IPStatus.TtlExpired && rep.Status != IPStatus.TimedOut && rep.Status != IPStatus.TimeExceeded;
}
However, remember that it is called an IPv4 mask for a reason - you can use it as one (so here is your algorithmic solution):
private static bool IsLanIP(IPAddress address)
{
var interfaces = NetworkInterface.GetAllNetworkInterfaces();
foreach (var iface in interfaces)
{
var properties = iface.GetIPProperties();
foreach (var ifAddr in properties.UnicastAddresses)
{
if (ifAddr.IPv4Mask != null &&
ifAddr.Address.AddressFamily == AddressFamily.InterNetwork &&
CheckMask(ifAddr.Address, ifAddr.IPv4Mask, address))
return true;
}
}
return false;
}
private static bool CheckMask(IPAddress address, IPAddress mask, IPAddress target)
{
if (mask == null)
return false;
var ba = address.GetAddressBytes();
var bm = mask.GetAddressBytes();
var bb = target.GetAddressBytes();
if (ba.Length != bm.Length || bm.Length != bb.Length)
return false;
for (var i = 0; i < ba.Length; i++)
{
int m = bm[i];
int a = ba[i] & m;
int b = bb[i] & m;
if (a != b)
return false;
}
return true;
}
Typically any IPs like 10.x.x.x (Class A) or 192.x.x.x (Class C) can be safely assumed to be inside a private local area network. IP Classications
One thing that you could possibly use is to try and communicate between clients using multicast. Most firewalls and routers would block multicast traffic (and ISPs most definitely), meaning that you wouldn't be able to join a multicast group if no other client is on the lan. A dumb switch would pass on the traffic, a layer 3-switch might block it, or could allow it depending on configuration. Either way, if the layer 3 switch block it, you are probably on different subnets altogether anyway so all other options would fail as well.
One technology that comes to mind is SSDP ( http://en.wikipedia.org/wiki/Simple_Service_Discovery_Protocol ) which would serve your purpose pretty good I believe. That way you don't really need to figure out if you are on a LAN or not, just search for another node that is actively downloading, if you can't find one, start downloading yourself.
Since SSDP is a standard used in uPnP you would probably be able to find decent implementations you could work with.

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()

How do I get the Local Network IP address of a computer programmatically?

I need to get the actual local network IP address of the computer (e.g. 192.168.0.220) from my program using C# and .NET 3.5. I can't just use 127.0.0.1 in this case.
How can I accomplish this?
If you are looking for the sort of information that the command line utility, ipconfig, can provide, you should probably be using the System.Net.NetworkInformation namespace.
This sample code will enumerate all of the network interfaces and dump the addresses known for each adapter.
using System;
using System.Net;
using System.Net.NetworkInformation;
class Program
{
static void Main(string[] args)
{
foreach ( NetworkInterface netif in NetworkInterface.GetAllNetworkInterfaces() )
{
Console.WriteLine("Network Interface: {0}", netif.Name);
IPInterfaceProperties properties = netif.GetIPProperties();
foreach ( IPAddress dns in properties.DnsAddresses )
Console.WriteLine("\tDNS: {0}", dns);
foreach ( IPAddressInformation anycast in properties.AnycastAddresses )
Console.WriteLine("\tAnyCast: {0}", anycast.Address);
foreach ( IPAddressInformation multicast in properties.MulticastAddresses )
Console.WriteLine("\tMultiCast: {0}", multicast.Address);
foreach ( IPAddressInformation unicast in properties.UnicastAddresses )
Console.WriteLine("\tUniCast: {0}", unicast.Address);
}
}
}
You are probably most interested in the UnicastAddresses.
Using Dns requires that your computer be registered with the local DNS server, which is not necessarily true if you're on a intranet, and even less likely if you're at home with an ISP. It also requires a network roundtrip -- all to find out info about your own computer.
The proper way:
NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
foreach(NetworkInterface adapter in nics)
{
foreach(var x in adapter.GetIPProperties().UnicastAddresses)
{
if (x.Address.AddressFamily == AddressFamily.InterNetwork && x.IsDnsEligible)
{
Console.WriteLine(" IPAddress ........ : {0:x}", x.Address.ToString());
}
}
}
(UPDATE 31-Jul-2015: Fixed some problems with the code)
Or for those who like just a line of Linq:
NetworkInterface.GetAllNetworkInterfaces()
.SelectMany(adapter=> adapter.GetIPProperties().UnicastAddresses)
.Where(adr=>adr.Address.AddressFamily == AddressFamily.InterNetwork && adr.IsDnsEligible)
.Select (adr => adr.Address.ToString());
In How to get IP addresses in .NET with a host name by John Spano, it says to add the System.Net namespace, and use the following code:
//To get the local IP address
string sHostName = Dns.GetHostName ();
IPHostEntry ipE = Dns.GetHostByName (sHostName);
IPAddress [] IpA = ipE.AddressList;
for (int i = 0; i < IpA.Length; i++)
{
Console.WriteLine ("IP Address {0}: {1} ", i, IpA[i].ToString ());
}
As a machine can have multiple ip addresses, the correct way to figure out your ip address that you're going to be using to route to the general internet is to open a socket to a host on the internet, then inspect the socket connection to see what the local address that is being used in that connection is.
By inspecting the socket connection, you will be able to take into account weird routing tables, multiple ip addresses and whacky hostnames. The trick with the hostname above can work, but I wouldn't consider it entirely reliable.
If you know there are one or more IPv4 addresses for your computer, this will provide one of them:
Dns.GetHostAddresses(Dns.GetHostName())
.First(a => a.AddressFamily == AddressFamily.InterNetwork).ToString()
GetHostAddresses normally blocks the calling thread while it queries the DNS server, and throws a SocketException if the query fails. I don't know whether it skips the network call when looking up your own host name.

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