获取在不同网络中连接的远程客户端的主机名和IP地址

Question

How do I retrieve IP address and hostname of the peer client requesting connection to my server.Both client and Server are connected in different networks

I tried getpeername()..But it gives the right IP address when both client and server are connected in same network.

Socket* SocketServer::Accept() 
{

    struct sockaddr_in cli_addr;
    struct hostent *hp;
   int clilen = 0;    
    clilen = sizeof (cli_addr);

    SOCKET new_sock = accept(s_, (struct sockaddr *) &cli_addr, &clilen);
    if (new_sock == INVALID_SOCKET) 
    {
        SetLastError( WSAGetLastError() );
       // std::cout<<"Socket invalid due to :"<<WSAGetLastError()<<endl;
        WSACleanup();
    }
    Socket* r = new Socket(new_sock);
    //std::cout<<" Accepted Connection"<<endl;

  int ret = getpeername(new_sock, (struct sockaddr *)&cli_addr, &clilen);

   struct sockaddr_in *s = (struct sockaddr_in *)&cli_addr;
   std::string ip = inet_ntoa(cli_addr.sin_addr);

  //cout << " The IP address from the accept is " << ip << std::endl;


  hp = gethostbyaddr((char *)&cli_addr.sin_addr,sizeof(cli_addr.sin_addr),AF_INET);
  std::string cliname;
  if (hp!=NULL)
   cliname  = hp->h_name;
   r->setDNS(cliname);
   r->setIP(ip);
    return r;
}

Answer 1

If I read your question correctly, the client is behind a NAT box that rewrites the source IP address and you want the original one. If that is the case, there's nothing you can do to find out "the real" IP address, short of asking the client to send it to you.