Question

I am trying to communicate with a telnet server via socket programming with wxWidgets however, after I connect to the server I don’t get any message back, even though I know there is a welcome message from the server, I just get nothing, is there a certain message I have to send to initiate a telnet session with the server, I thought just connecting would be good enough that it would then send the welcome message. When I connect via putty the server gives a welcome message right away before any input from me.

Can I get a link to a specification which will detail how to initiate a telnet session cause I haven’t been able to find a useful article yet from searching.

Answer 1

The following program connects to a telnet server and prints the data it receives. Notice that the data is binary, not text — you need to study the RFC854 to understand how to parse the telnet protocol.

#include <wx/wx.h>
#include <wx/socket.h>
#include <iostream>
#include <iomanip>

int main () {
  wxInitialize();
  wxSocketClient sockConn(wxSOCKET_WAITALL);
  wxIPV4address addr;
  addr.Hostname(wxT("shell.theworld.com"));
  addr.Service(23);
  if(!sockConn.Connect(addr, true)) {
    std::cout << "Connect failed\n";
    return 1;
  }
  std::string s(' ', 10);
  sockConn.Read(&s[0], 10);
  for(unsigned char c : s)
    std::cout << std::hex << (unsigned int)c << " ";
  std::cout << "\n";
  wxUninitialize();
  return 0;
}