iTP Secure WebServer System Administrators Guide (Version 7.5+)

subnet address. An extension of the Internet addressing scheme that allows a site to use a single Internet address
for multiple physical networks. Outside of the site using subnet addressing, routing continues as
usual by dividing the destination address into an Internet portion and local portion. Gateways
and hosts inside a site using subnet addressing interpret the local portion of the address by
dividing it into a physical network portion and host portion.
subsystem. The software or hardware facilities that provide users with access to a set of communications
services.
TCP Delayed
Acknowledgements.
For every data packet received, TCP/IP sends an 'ACK' packet for synchronization purposes.
This is done in order to ensure that the data packet has reached its destination. If anything goes
wrong with the data packet during transmission, the acknowledgement packet 'ACK' will not be
received at the sender's end. In this condition, the data packet will be re-transmitted. There is a
fair possibility that these 'ACK' packets may cause the network congestion. TCP Delayed
Acknowledgments is a feature introduced into TCP which uses the Delayed ACK Algorithm, by
default with a delay timer of 200 milliseconds. It does not send an ACK right away. The hope is
to have data ready in that time frame of 200 milliseconds. Then, the 'ACK' can be sent
(piggy-backed) along with a data segment.
TELNET. The Internet standard protocol for remote terminal connection service. TELNET allows a user at
one site to interact with remote timesharing systems at another site just as if the user’s terminal is
connected directly to the remote machine. That is, the user invokes a TELNET application program
that connects to a remote machine, prompts for a login ID and password, and then passes
keystrokes from the user’s terminal to the remote machine and displays output from the remote
machine on the user’s terminal.
Transmission
Control Protocol
(TCP).
The Internet standard transport-level protocol that provides the reliable, full-duplex stream service
on which many application protocols depend. TCP allows a process on one machine to send a
stream of data to a process on another. It is connection-oriented, in the sense that before
transmitting data participants must establish a connection. Software implementing TCP usually
resides on the operating system and uses the Internet Protocol (IP) to transmit information across
the Internet. It is possible to terminate (shut down) one direction of flow across a TCP connection,
leaving a one-way (simplex) connection. The Internet protocol suite is often referred to as TCP/IP
because TCP is one of the two most fundamental protocols.
Transport Layer
Security (TLS).
A security protocol that provides a secure channel for private communication on the World Wide
Web, through encryption and authentication.
Unicode. The 16-bit character encoding used by Java for the char and java.lang.String data types.
URL. Uniform Resource Locator.
wait mode. In the NonStop operating system, the mode in which the called procedure waits for the completion
of an input/output (I/O) operation before returning a condition code to the caller. Compare
nowait mode.
Web clients. Programs that execute on IBM-compatible PC, Apple Macintosh, or Unix platforms, among others.
They provide a graphic user interface (GUI) for access to documents and programs on the Web.
A Web browser is the most familiar example of a Web client.
Web Container. A Java run-time environment that manages the lifecycle of servlets and JSP.
Web server. Web servers are programs that execute on a variety of server platforms. These include
IBM-compatible servers, Apple Macintosh servers, Unix servers, and a large number of proprietary
hosts. Web server functions can be divided into two parts. A file server part performs normal file
server functions such as file transfer and buffering. A message switching facility allows messages
from Web clients to be forwarded to application programs.
World Wide Web
(WWW) protocols.
The WWW protocols were first defined by the CERN project in Switzerland and were later
extended by a number of groups, most notably by the National Center for SuperComputing
Applications (NCSA) at the University of Illinois. These WWW protocols were originally developed
to improve communications over the Internet by providing the ability to access and display
Web-client hardware-independent documents that not only contained ASCII text but that also
contained pictures, graphics, and voice and video elements. In addition to accessing documents,
the WWW protocols can also be used to provide document searching facilities and also interaction
with user-written or vendor-provided servers.
WWW. See World Wide Web (WWW) protocols..
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