Webrequest.BeginGetResponse is slow - alternative to verifying destination exists before getting blocked on Async call?

I'm having this situation: webrequest.begingetresponse is taki开发者_StackOverflow中文版ng too much time when the url is invalid

However I notice that the PING command doesn't take the same amount of time. Anyone know the equivalent .net call that ping is making?

Doh(!) System.Net.NetworkInformation.Ping()