iTP Secure WebServer System Administrator's Guide (iTPWebSvr 6.0+)

Introduction to the iTP Secure WebServer
iTP Secure WebServer System Administrator’s Guide—523346-002
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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 HP NonStop 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, conventional TCP/IP has one listening process on each 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, Parallel Library TCP/IP has 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 HP 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 running. As a result, a TCPMON
(the monitor process) runs 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.