Cannot retrieve hostname calling my TCPListener Service

问题

I am writing a simple FTP service using TcpListener and would like to find out what hostname (domain with multiple subdomains) the incoming call is using.

Is this possible?

//Barebone TCPListener example
System.Net.Sockets.TcpListener listener;
listener = new TcpListener(IPAddress.Any, 21)

listener.Start();

TcpClient client = listener.AcceptTcpClient();

//Great, incoming... what domain are they using to call my service?

//This only gives me the local and remote IP..
//IPEndPoint LocalEndPoint = (IPEndPoint)client.Client.LocalEndPoint;
//IPEndPoint RemoteEndPoint = (IPEndPoint)client.Client.RemoteEndPoint;

Any pointers greatly appreciated.

回答1:

I don't think TCP fundamentally has that information. That's why HTTP has the "Host" header so clients can specify it.

Essentially, making a TCP connection to a host name is equivalent to resolving the host name into an address, then making the connection as if there'd never been a name.

来源：https://stackoverflow.com/questions/12706901/cannot-retrieve-hostname-calling-my-tcplistener-service