Glossary
GL-10
User Guide for Cisco Secure Access Control System 5.4
OL-26225-01
G
gateway A network point that acts as an entrance to another network.
global system
options
Configuring TACACS+, EAP-TTLS, PEAP, and EAP-FAST runtime characteristics and generating
EAP-FAST PAC.
H
hash functions Used to generate a one way "check sum" for a larger text, which is not trivially reversed. The result
of this hash function can be used to validate if a larger file has been altered, without having to compare
the larger files to each other. Frequently used hash functions are MD5, SHA1, and SHA2.
header The extra information in a packet that is needed for the protocol stack to process the packet.
host Any computer that has full two-way access to other computers on the Internet. Or a computer with a
web server that serves the pages for one or more Web sites.
Host-Based ID Host-based intrusion detection systems use information from the operating system audit records to
watch all operations occurring on the host that the intrusion detection software has been instal led
upon. These operations are then compared with a pre-defined security policy. This analysis of the audit
trail imposes potentially significant overhead requirements on the system because of the increased
amount of processing power which must be utilized by the intrusion detection system. Depending on
the size of the audit trail and the processing ability of the system, the review of audit data could result
in the loss of a real-time analysis capability.
HTTPS Hypertext Transfer Protocol over Secure Socket Layer, or HTTP over SSL. HTTPS is a Web protocol
developed by Netscape and built into its browser that encrypts and decrypts user page requests as well
as the pages that are returned by the Web server. When used in the first part of a URL (the part that
precedes the colon and specifies an access scheme or protocol), this term specifies the use of HTTP
enhanced by a security mechanism, which is usually SSL.HTTPS uses port 443 instead of HTTP port
80 in its interactions with the lower layer, TCP/IP and an additional encryption/authentication layer
between HTTP and TCP.
hub A network device that operates by repeating data that it receives on one port to all the other ports. As
a result, data transmitted by one host is retransmitted to all other hosts on the hub. The central device
in a star network, whether wired or wireless. Wireless access points act as hubs in wireless n etworks.
hybrid attack Builds on the dictionary attack method by adding numerals and symbols to dictionary words.
hybrid encryption An application of cryptography that combines two or more encryption algorithms, particularly a
combination of symmetric and asymmetric encryption.
(HTML Hypertext Markup Language. The set of markup symbols or codes inserted in a file intended for
display on a World Wide Web browser page.
(HTTP Hypertext Transfer Protocol. The protocol in the Internet Protocol (IP) family used to transport
hypertext documents across an internet.