Appliance Trim Kit User Manual

Appendix A: Glossary
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cache efficiency A tab found on the Statistics pages of the Management Console that shows the
percent of objects served from cache, the percent loaded from the network, and the
percent that were non-cacheable.
cache hit Occurs when the SG appliance receives a request for an object and can serve the
request from the cache without a trip to the origin server.
cache miss Occurs when the appliance receives a request for an object that is not in the cache.
The appliance must then fetch the requested object from the origin server. .
cache object Cache contents includes all objects currently stored by the SG appliance. Cache
objects are not cleared when the SG appliance is powered off.
Certificate Authority (CA) A trusted, third-party organization or company that issues digital certificates used to
create digital signatures and public key/private key pairs. The role of the CA is to
guarantee that the individuals or company representatives who are granted a unique
certificate are who they claim to be.
child class (bandwidth gain) The child of a parent class is dependent upon that parent class for available
bandwidth (they share the bandwidth in proportion to their minimum/maximum
bandwidth values and priority levels). A child class with siblings (classes with the
same parent class) shares bandwidth with those siblings in the same manner.
client consent certificates A certificate that indicates acceptance or denial of consent to decrypt an end user's
HTTPS request.
client-side transparency A way of replacing the appliance IP address with the Web server IP address for all
port 80 traffic destined to go to the client. This effectively conceals the SG appliance
address from the client and conceals the identity of the client from the Web server.
concentrator An SG appliance, usually located in a data center, that provides access to data center
resources, such as file servers.
content filtering A way of controlling which content is delivered to certain users. SG appliances can
filter content based on content categories (such as gambling, games, and so on), type
(such as http, ftp, streaming, and mime type), identity (user, group, network), or
network conditions. You can filter content using vendor-based filtering or by
allowing or denying access to URLs.
D
default boot system The system that was successfully started last time. If a system fails to boot, the next
most recent system that booted successfully becomes the default boot system.
default proxy listener See proxy service (d efault).
denial of service (DoS) A method that hackers use to prevent or deny legitimate users access to a computer,
such as a Web server. DoS attacks typically send many request packets to a targeted
Internet server, flooding the server's resources and making the system unusable. Any
system connected to the Internet and equipped with TCP-based network services is
vulnerable to a DoS attack.
The SG appliance resists DoS attacks launched by many common DoS tools. With a
hardened TCP/IP stack, SG appliance resists common network attacks, including
traffic flooding.