Dns.GetHostEntry Method (String)

Resolves a host name or IP address to an IPHostEntry instance.

Namespace: System.Net
Assembly: System (in system.dll)

public static IPHostEntry GetHostEntry (
	string hostNameOrAddress
public static IPHostEntry GetHostEntry (
	String hostNameOrAddress
public static function GetHostEntry (
	hostNameOrAddress : String
) : IPHostEntry
Not applicable.



The host name or IP address to resolve.

Return Value

An IPHostEntry instance that contains address information about the host specified in hostNameOrAddress.

Exception typeCondition


The hostNameOrAddress parameter is a null reference (Nothing in Visual Basic).


The length of hostNameOrAddress parameter is greater than 126 characters.


An error was encountered when resolving the hostNameOrAddress parameter.


The hostNameOrAddress parameter is an invalid IP address.

The GetHostEntry method queries a DNS server for the IP address that is associated with a host name or IP address.

When an empty string is passed as the host name, this method returns the IPv4 addresses of the local host.

If the host name could not be found, the SocketException exception is returned with a value of 11001 (Windows Sockets error WSAHOST_NOT_FOUND). This exception can be returned if the DNS server does not respond. This exception can also be returned if the name is not an official host name or alias, or it cannot be found in the database(s) being queried.

The ArgumentException exception is also returned if the hostNameOrAddress parameter contains Any or IPv6Any.


This member emits trace information when you enable network tracing in your application. For more information, see Network Tracing.

The following example uses the GetHostEntry method to resolve an IP address to an IPHostEntry instance.

public static void DoGetHostEntry(string hostname)
    IPHostEntry host;

    host = Dns.GetHostEntry(hostname);

    Console.WriteLine("GetHostEntry({0}) returns:", hostname);

    foreach (IPAddress ip in host.AddressList)
        Console.WriteLine("    {0}", ip);

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

.NET Compact Framework

Supported in: 2.0

Community Additions