How to Get the Local Network Ip Address of a Computer Programmatically

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

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 ()); 
}

Get local 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();

How to get the local IP of the PC?

You are missing to filter the IP by type (v4). Anyway you can have multiple IP v4 addresses on your PC (for example you can have 2 interfaces, LAN and Wi-Fi).

The following code gets the list of available IP v4.

List<string> ips = new List<string>();

System.Net.IPHostEntry entry = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName());

foreach (System.Net.IPAddress ip in entry.AddressList)
    if (ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
        ips.Add(ip.ToString());

Programmatically finding IP address of another computer on LAN

Ok, gethostbyname() always works when trying to find the ip address given a hostname, as long as the hostname of the computer you ae trying to access has its name registered in a DNS Server. All comments and answers above were useful.

Find server ip address on local network

You could use the hostname of the server instead of the IP. When IP changes the hostname should stay the same.

You can establish the hostname in many ways. Either programmatically:

 String hostName = InetAddress.getLocalHost().getHostName();

Or with an OS command or a tool.

For example, on Windows it could be

ipconfig /all

On Linux it could probably be

hostname

or

hostnamectl

Once you know the hostname you could use it to establish a connection. Alternatively, you could also get the IP of the server programmatically on any client in the local network. In Java you could use the following code:

InetAddress.getByName("serverHostName").getHostAddress()

Finding local IP addresses using Python's stdlib

import socket
socket.gethostbyname(socket.gethostname())

This won't work always (returns 127.0.0.1 on machines having the hostname in /etc/hosts as 127.0.0.1), a paliative would be what gimel shows, use socket.getfqdn() instead. Of course your machine needs a resolvable hostname.

Getting the IP address of the current machine using Java

import java.net.DatagramSocket;
import java.net.InetAddress;

try(final DatagramSocket socket = new DatagramSocket()){
  socket.connect(InetAddress.getByName("8.8.8.8"), 10002);
  ip = socket.getLocalAddress().getHostAddress();
}

This way works well when there are multiple network interfaces. It always returns the preferred outbound IP. The destination 8.8.8.8 is not needed to be reachable.

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.

Edit:

As @macomgil says, for MacOS you can do this:

Socket socket = new Socket();
socket.connect(new InetSocketAddress("google.com", 80));
System.out.println(socket.getLocalAddress());

How can I get computer name and IP address of local computer

Have a look at this: link

and this: link

textBox1.Text = "Computer Name: " + Environment.MachineName

textBox2.Text = "IP Add: " + Dns.GetHostAddresses(Environment.MachineName)[0].ToString();

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