Following small sample (using WMI/System.Management), dumps some of  the
"connected" adapter's configuration info ...

using System;
using System.Management;

class Sample_NeworkSelectQuery
{
   enum NetConnectionStatus
   {
       Connecting = 1,
       Connected,
       Disconnecting,
       Hardware_not_present,
       Hardware_disabled,
       Hardware_malfunction
   }
   public static void Main(string[] args)
   {
       // search for the physical adapters with connection status = 2
(connected)
       string q = string.Format("Select DeviceId, NetConnectionStatus ,
NetConnectionID from Win32_NetworkAdapter where PhysicalAdapter='{0}' and
NetConnectionStatus={1}",
           true,
           (int)NetConnectionStatus.Connected);

       SelectQuery selectQuery = new SelectQuery(q);
       using(ManagementObjectSearcher adapterSearcher = new
ManagementObjectSearcher(selectQuery))
       {
           foreach (ManagementObject adapter in adapterSearcher.Get())
           {
               Console.WriteLine("{0},
{1}",adapter["NetConnectionStatus"].ToString(),
adapter["NetConnectionID"].ToString());
               RelatedObjectQuery adapterRelatedQuery =
    new RelatedObjectQuery ("associators of
{Win32_NetworkAdapter.DeviceId='" + adapter["DeviceId"]+ "'}");
                   adapterRelatedQuery.RelatedClass =
"Win32_NetworkAdapterConfiguration";
               using(ManagementObjectSearcher adapterConfigSearcher = new
ManagementObjectSearcher(adapterRelatedQuery))
               {
                   foreach (ManagementObject adapterConfig in
adapterConfigSearcher.Get())
                   {
                       foreach(string ip in adapterConfig["IPAddress"] as
Array)
                           Console.WriteLine("\tIpAddress: {0}", ip);
                   }
               }
           }
       }
   }
}

Willy.