RE: Sockets problem (what is)

[Buck Calabro <Buck.Calabro@xxxxxxxxxxxx>]

Ron wrote:

>Its these two that I'm not sure of:
>
>s-msg to client 'move to port 999'
>c-msg to server 'understood'

Sorry.  My brain is still on holiday it appears!  What I mean to say is that
is the server is really going to move the connexion to another port, they
have got to tell the client in some way.  If they just stop listening on the
original port they will have essentially disconnected without telling the
client.

So the server must have some way of saying "Hey!  I'm about to move over to
port 999 - tell me when you're ready"  Then the server should listen for the
client to answer "OK, I'm ready." before moving over.

Like Jim says, this is most probably determined by the server program, and
not some inherent TCP/IP mechanism.  All of this discussion is contingent
upon the server actually changing PORTs, and not doing some "server-internal
task switch" that Scott is talking about.  Scott's scenario should be very
transparent to the client.  Perhaps a few more details of what's going on
would clear things up a bit.

1) Is this a standard TCP/IP service like
   Telnet, FTP, SMTP or a custom-written server?
   Knowing the port you originally connect to
   might be a clue here.
2) If custom-written, is there documentation on
   the protocol to use the server?  Stuff like
   how to sign on, log off and so on.
3) Did the vendor provide the socket client or
   was it written 'in-house?'  If in-house, are
   you always checking the return code and err no?

  --buck