iTP Secure WebServer System Administrator's Guide (iTPWebSvr 5.1+)

Introduction to the iTP Secure WebServer
iTP Secure WebServer System Administrator’s Guide—522659-001
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Web Clients
Web Clients
Web clients, such as browsers, are programs that provide a graphical user interface
(GUI) to web servers such as the iTP Secure WebServer.
TCP/IP Subsystem
The Compaq TCP/IP subsystem allows processes on a NonStop System to communicate
using the TCP/IP protocol. There are two versions of TCP/IP support available;
Conventional and Parallel Library.
Conventional TCP/IP
In essence, one listening process per port. The conventional TCP/IP connections are
managed by the Distributor process. The Distributor receives all incoming requests for
new connections from the TCP/IP processes and distributes them to the iTP Secure
WebServer, using the NonStop TS/MP Pathsend facility.
Parallel Library TCP/IP
In essence, multiple listener sockets on the same port. Parallel Library TCP/IP allows
the server direct access to the communication environment from it’s own CPU instead of
having to communicate via the CPU that contains the Compaq TCP/IP process. This is
done by linking to a system library containing the TCP/IP procedures and allowing the
server to call the functions doing TCP/IP-related processing in its own context.
Running with the Auto-Accept feature, an iTP WebServer no longer needs its Distributor
component. The httpd servers will assume the listening as well as the distributing
functions of the Distributor. The Distributor server class will be completely removed
from the PATHWAY environment.
Running the iTP WebServer relies on the properly configured Parallel Library TCP/IP
environment. Every CPU specified in the Server CPUS command (in the httpd.config
configuration file) needs to be enabled to run Parallel Library TCPIP. In other words, the
TCPMAN needs to be properly configured and run. As a result, there is a TCPMON (the
monitor process) running on every CPU specified in the Server’s CPUS command.
Unlike the conventional TCP/IP subsystem, the Parallel Library TCPIP allows the iTP
WebServer to create a listening socket on each of these CPUs. By creating a listening
socket on each of these CPUs, the httpd servers provide the listening capability for
themselves. Therefore, mixing the Parallel Library TCPIP with conventional TCP/IP
subsystem is not permissible. If both TCPSAM process and conventional TCP/IP
process are specified as the transport service providers, the Auto-Accept feature will not
be enabled. The iTP WebServer will be running as a conventional TCP/IP configuration.