[comp.protocols.tcp-ip.ibmpc] client-server architecture using NCSA telnet

krodgers@boulder.Colorado.EDU (Kevin Rodgers) (08/21/90)

[I'm posting this for a friend who doesn't have access to usenet; please
reply to bill@b52.den.mmc.com; don't followup]



   We are trying to build a database server-like software system
that consists of a server and many clients on a ethernet LAN.
The server will listen for connections from any of the clients.
The clients will repeatedly request connects to the server to
retrieve information.  Once the retrieve is complete the client
will disconnect from the server, freeing the server to respond to
other clients.  We are experiencing difficulties using NSCA telnet
to implement this architecture. 

  Here is the simplified code of the client:

      client_main
      {
         Snetinit();

         do {
           interact_with_user();
           Snetopen();
           netwrite();
           netread();
           netclose();
         } while(!done);
      }


  Here is the simplified code for the server:

      server_main
      {
         Snetinit();
         diddy = 1;

         do {
            netlisten();
            netread();
            netwrite();
            netclose();
         } while(diddy); /* the dreaded do wa diddy */
      }


    This code seems to work perfectly the first time through.  On
subsequent connections problems start to appear. The most significant
seems to be that the client is receiving a packet for an invalid port
(error message is "Packet received for invalid port -- reset sent").
Most client programs like lpr, tend to always do a netshut and then
the program exits.  We are hoping to avoid reinitializing (netinit)
and shutting down (netshut) the hardware everytime the client wants 
to connect to the server.  

    Question: Has anyone written some NSCA telnet code that does a
simple server-client architecture?  or does anyone have any pointers
on how to do this?  Any help would be appreciated.

   Please send e-mail to:

   bill@b52.den.mmc.com


   Thanks,

   Bill Pardee 
   

Kevin Rodgers                           krodgers@boulder.colorado.edu
Department of Computer Science          GO BUFFS!
University of Colorado
Boulder CO 80309-0430