I like the WMILinq solution. While not exactly the solution to your problem, find below a taste of it :
using (WmiContext context = new WmiContext(@"\\.")) {
context.ManagementScope.Options.Impersonation = ImpersonationLevel.Impersonate;
context.Log = Console.Out;
var dnss = from nic in context.Source<Win32_NetworkAdapterConfiguration>()
where nic.IPEnabled
select nic;
var ips = from s in dnss.SelectMany(dns => dns.DNSServerSearchOrder)
select IPAddress.Parse(s);
}