In this type of service, data is cached and discarded entirely
on the basis of object size, popularity, or time since the
requested object was last updated in the cache. Frequently referred
to as on-demand caching because all caching updates are
user-initiated. See also active caching.
A TCP/IP utility that verifies connections to one or more
remote computers by sending ICMP packets and listening for reply
packets.
plug-in
A third-party application that is installed to extend and
enhance the functionality of ISA Server.
Point-to-Point
Protocol (PPP)
A communications protocol that allows a computer to connect to
other computers over a standard dial-up telephone line using a
high-speed modem.
Point-to-Point
Tunneling Protocol (PPTP)
A networking protocol that enables remote users to access
corporate networks securely across the Internet by dialing into an
Internet service provider (ISP) or by connecting directly to the
Internet. PPTP supports multiprotocol virtual private networks
(VPNs). Because PPTP allows multiprotocol encapsulation, users can
send any packet type over an IP network.
POP
See Post Office Protocol (POP).
popularity
A measure of the frequency with which objects or URLs are
requested by client applications, such as Web browsers. See also
cache.
port number
A number that identifies a certain Internet application with a
specific connection. Ports are used in TCP to name the ends of
logical connections that carry long-term conversations.
Post Office
Protocol (POP)
A network protocol that permits a client computer to access
e-mail on a server. Usually, this means that a POP3 server is used
to allow a client computer to retrieve mail that an SMTP server is
holding for it.
A software program that connects a user to a remote destination
through an intermediary gateway.
proxy client
A client computer that must use a proxy server to gain access
to network services not directly supported for client usage.
proxy server
A computer that acts as a relay between remote servers and
clients to intercept requests and process communications on behalf
of proxy clients.
publishing
The process that allows computers remote from an ISA Server
computer to publish to the Internet. Publishing includes reverse hosting and
secure Web
publishing.