Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

How can I communicate with Telnet Server?

Posted on 1998-07-21
1
Medium Priority
?
223 Views
Last Modified: 2013-12-03
Hi
Recently,I should make some application that using telnet.
So I got some telnet client code that is very simple.

But I couldn't understand some part of this program that communicate wiht telnet server
Untill using of connect() function in the below of program example, I can understand.
Afterthat this program send some bytes to telnet server.

I thought that is some specification of telnet protocol, but I don't have any information about that
I marked that section in the program......Please take a look!
I need any kind of help....I am in a hurry
I appreciate all of help...

Here is parts of telnet client.

int connect_server(void)
{
gg=WSAStartup(0x0101,&ws);
if (gg!=0) {MessageBox(0,error_WSAStartup(WSAGetLastError()),"error",0);return -1;}

//SendMessage(0,hwndChk,0,(LPARAM) (LPSTR) "try to open socket");
s = socket(AF_INET,SOCK_STREAM,0);
if (s==INVALID_SOCKET) {MessageBox(0,error_socket(WSAGetLastError()),"error",0);return -1;}

A.sin_family = AF_INET;
A.sin_port = htons(23);

//SendMessage(0,hwndChk,0,(LPARAM) (LPSTR) "try to get host name");
H=gethostbyname(szSERVERt);
if (H==NULL) {MessageBox(0,"cannot get host","error",0); return-1;}
           
A.sin_addr.s_addr=*((unsigned long *) H->h_addr);


//SendMessage(0,hwndChk,0,(LPARAM) (LPSTR) "try to connect");
d=connect(s,(struct sockaddr *)&A,sizeof(A));
if (d!=0) {MessageBox(0,"cannot connect","error",0);}

------ I can understand above of this line
------ Next line  I couldn't understand.
------ they send s1 that i don't know what it means.
                                                         
s1[0]= (unsigned char) 0xff;s1[1]=(unsigned char) 0xfb;s1[2]=(unsigned char)0x18;
send(s,s1,3,0);
s1[0]= (unsigned char) 0xff;s1[1]=(unsigned char) 0xfc;s1[2]=(unsigned char) 0x20;
send(s,s1,3,0);
s1[0]= (unsigned char) 0xff;s1[1]=(unsigned char) 0xfc;s1[2]=(unsigned char) 0x23;
send(s,s1,3,0);
s1[0]= (unsigned char) 0xff;s1[1]=(unsigned char) 0xfc;s1[2]=(unsigned char) 0x24;
send(s,s1,3,0);

hear("CONNECT 1");
s2[0]=(unsigned char) 0xff;s2[1]=(unsigned char) 0xfa;s2[2]=(unsigned char) 0x18;s2[3]=0x0;s2[4]=0x76;s2[5]=(unsigned char) 0x74;
s2[6]=(unsigned char) 0x31;s2[7]=(unsigned char)0x30;s2[8]=(unsigned char)0x30;s2[9]=(unsigned char)0xff;s2[10]=(unsigned char)0xf0;
send(s,s2,11,0);

hear("CONNECT 2");
s1[0]= (unsigned char)0xff;s1[1]=(unsigned char)0xfd;s1[2]=(unsigned char)0x03;
send(s,s1,3,0);
s1[0]= (unsigned char)0xff;s1[1]=(unsigned char)0xfb;s1[2]=(unsigned char)0x01;
send(s,s1,3,0);
s1[0]= (unsigned char)0xff;s1[1]=(unsigned char)0xfc;s1[2]=(unsigned char)0x1f;
send(s,s1,3,0);
s1[0]= (unsigned char)0xff;s1[1]=(unsigned char)0xfe;s1[2]=(unsigned char)0x05;
send(s,s1,3,0);
s1[0]= (unsigned char)0xff;s1[1]=(unsigned char)0xfc;s1[2]=(unsigned char)0x21;
send(s,s1,3,0);
0
Comment
Question by:folktale
1 Comment
 
LVL 23

Accepted Solution

by:
chensu earned 200 total points
ID: 1410712
Look into
TELNET PROTOCOL SPECIFICATION
http://www.faqs.org/rfcs/rfc854.html

There are details.
0

Featured Post

Vote for the Most Valuable Expert

It’s time to recognize experts that go above and beyond with helpful solutions and engagement on site. Choose from the top experts in the Hall of Fame or on the right rail of your favorite topic page. Look for the blue “Nominate” button on their profile to vote.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article describes how to add a user-defined command button to the Windows 7 Explorer toolbar.  In the previous article (http://www.experts-exchange.com/A_2172.html), we saw how to put the Delete button back there where it belongs.  "Delete" is …
With most software applications trying to cater to multiple user needs nowadays, the focus is to make them as configurable as possible. For e.g., when creating Silverlight applications which will connect to WCF services, the service end point usuall…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
Integration Management Part 2

972 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question