Calling System.Net.Dns.GetHostEntry(sHostName) failed

Hi all, T$$anonymous$$s should not be a new problem, but I couldn't find any answers on the internet, here's the detail:

I use:

 string sHostName = System.Net.Dns.GetHostName();

to get the host name and pass it to the following code:(the hostname is 'bogon')

 System.Net.IPHostEntry hostEntry = System.Net.Dns.GetHostEntry(sHostName); 

but I got an exception: "System.Net.Sockets.SocketException: No such host is known..... balabala..."

my dev environment is mac Unity editor 5.5.1f1, hope anyone can help me, Thanks!