The Question is:
A Visual Basic application running on a PC is senting data via socket 80 (http
msg) to the VMS machine that is running a "C" program. This program opens
socket 80 and receives the message, but when a returned message is sent it is
sent via telnet and not
over port 80. How do you make the VMS "C" routine use port 80 to send and
receive using the http protocol.
The Answer is :
Port 80 is the default port for the hypertext transport protocol
(http), of course.
The application code is apparently opening the telnet port for the
response. The usual C socket calls are available, and are detailed
in the TCP/IP Services manual and in the appendix of the C Run-Time
Library Reference Manual, and in various available examples.
You will typically want to send and receive http messages on port 80,
meaning that you are effectively creating some or all of a web server.
(If you want to see how the Apache web server does this, source code
is available.) Or you bring up an actual web server on OpenVMS (Apache
or otherwise), and use one or more CGI scripts to process the traffic.
Examples of DCL CGI are available here in the Ask The Wizard area.