C# Code Snippet - Get local computer IP address

C# Code Snippet - Get local computer IP address

This .Net C# code snippet get the IP address from the local machine. This function uses System.Net namespace to get local machine hostname and then get a array of IPAddress objects. Modify the exception handling section to meet your project requirements.

/// <summary>
/// Gets IP addresses of the local computer
/// </summary>
public string GetLocalIP()
{
    string _IP = null;

    // Resolves a host name or IP address to an IPHostEntry instance.
    // IPHostEntry - Provides a container class for Internet host address information. 
    System.Net.IPHostEntry _IPHostEntry = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName());

    // IPAddress class contains the address of a computer on an IP network. 
    foreach (System.Net.IPAddress _IPAddress in _IPHostEntry.AddressList)
    {
        // InterNetwork indicates that an IP version 4 address is expected 
        // when a Socket connects to an endpoint
        if (_IPAddress.AddressFamily.ToString() == "InterNetwork")
        {
            _IP = _IPAddress.ToString();
        }
    }
    return _IP;
}

Here is a simple example showing how to use above function (GetLocalIP) to display local machine IP address.

Console.WriteLine("Local computer IP address : " + GetLocalIP());

This .Net code snippet gets the array of all the IPAddress objects. Use this method if you are writing sockets applications, a computer can have multiple IP addresses with one or more NIC cards.

/// <summary>
/// Gets IP addresses object list from the local computer
/// </summary>
public System.Net.IPAddress[] GetLocalIPList()
{
    // Resolves a host name or IP address to an IPHostEntry instance.
    // IPHostEntry - Provides a container class for Internet host address information. 
    System.Net.IPHostEntry _IPHostEntry = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName());

    return _IPHostEntry.AddressList;
}

Here is a simple example showing how to use above function (GetLocalIPList) to display all the IP addresses from local machine.

// display all IP addresses of local machine
foreach (System.Net.IPAddress _IPAddress in GetLocalIPList())
    Console.WriteLine(_IPAddress.ToString());


// display all IP addresses of local machine with addressing scheme
foreach (System.Net.IPAddress _IPAddress in GetLocalIPList())
    Console.WriteLine(_IPAddress.AddressFamily.ToString() + " = " +  _IPAddress.ToString());

C# Keywords Used:

• DNS
• IPAddress
• GetHostEntry
• IPHostEntry
• AddressList
• AddressFamily
• InterNetwork
• Exception

Code Snippet Information:

• Applies To: Visual Studio, .Net, C#, CLI, DNS, Domain Name System, IPAddress, GetHostEntry, IPHostEntry, AddressFamily, InterNetwork, Socket programming, Networking, Network monitoring
• Programming Language : C# (C-Sharp)

External Resources:

• Dns.GetHostEntry Method (String)
• IPHostEntry Class
• IPAddress Class
• IPHostEntry.AddressList Property
• AddressFamily Enumeration
• Exception Class

Sonny Eugenio :: August 12-2010 :: 08:20 AM

Is it possible to get the local IP address of the first network adapter directly without looping through the IP list.

JP van Mackelenbergh :: January 27-2011 :: 04:26 PM

Whats up with this:
if (_IPAddress.AddressFamily.ToString() == "InterNetwork")

AddressFamily is an enumeration, so please give a good example :)
if (_IPAddress.AddressFamily == AddressFamily.InterNetwork)

Leave a comment