Mono Documentation

Resolves a DNS host name or IP address to a System.Net.IPHostEntry instance. [Edit]

[System.Obsolete("Use GetHostEntry instead")]
public static IPHostEntry Resolve (string hostName)

Parameters

hostName
A string containing a DNS-style host name or IP address. [Edit]

Returns

A System.Net.IPHostEntry instance containing address information about the host specified in hostName . [Edit]

Permissions

Type Reason
System.Net.DnsPermission [Edit] Requires unrestricted permission for accessing DNS information. This method also asserts unrestricted DnsPermission . See System.Net.DnsPermission and System.Security.Permissions.PermissionState.Unrestricted.

Type	Reason
System.Net.DnsPermission [Edit]	Requires unrestricted permission for accessing DNS information. This method also asserts unrestricted `DnsPermission` . See System.Net.DnsPermission and System.Security.Permissions.PermissionState.Unrestricted.

Exceptions

Type Reason
ArgumentNullException hostName is null . [Edit]
System.Net.Sockets.SocketException An error was encountered executing the DNS query . [Edit]
System.Security.SecurityException The caller does not have permission to access DNS information. [Edit]

Type	Reason
ArgumentNullException	hostName is `null` . [Edit]
System.Net.Sockets.SocketException	An error was encountered executing the DNS query . [Edit]
System.Security.SecurityException	The caller does not have permission to access DNS information. [Edit]

Remarks

The Dns.Resolve(string) method queries a DNS server for the IP address associated with a host name or an IP address in dotted-quad notation.
When hostName is a DNS-style host name associated with multiple IP addresses, only the first IP address that resolves to that host name is returned.
[Edit]

Example

The following example demonstrates the use of the Dns.Resolve(string) method.

C# Example

using System;
using System.Net;

public class DnsTest {
 public static void Main() {
   IPHostEntry hostInfo1 = Dns.Resolve("www.contoso.com");
   DisplayHostInfo(hostInfo1);
   Console.WriteLine();
 }

 public static void DisplayHostInfo(IPHostEntry hostInfo) {
   string[] aliases = hostInfo.Aliases;
   IPAddress[] addresses = hostInfo.AddressList;
   Console.WriteLine("The host name is: {0}", hostInfo.HostName);

   for(int x = 0; x < aliases.Length; x++)
     Console.WriteLine("Alias {0} == {1}", aliases[x], addresses[x]);
 }
}

The output is

The host name is: contoso.com Alias www.contoso.com == 207.46.230.186

Requirements

Namespace: System.Net
Assembly: System (in System.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0