Ve vb.net to je podobne.
string input = "vase ip";
IPAddress address;
if (IPAddress.TryParse(input, out address))
{
switch (address.AddressFamily)
{
case System.Net.Sockets.AddressFamily.InterNetwork:
// IPv4
break;
case System.Net.Sockets.AddressFamily.InterNetworkV6:
// IPv6
break;
default:
// umm...
break;
}
}