Glossary
GL-8
Cisco Security Appliance Command Line Configuration Guide
OL-12172-03
H.323
Allows dissimilar communication devices to communicate with each other by using a standardized
communication protocol. H.323 defines a common set of CODECs, call setup and negotiating
procedures, and basic data transport methods.
H.323 RAS
Registration, admission, and status signaling protocol. Enables devices to perform registration,
admissions, bandwidth changes, and status and disengage procedures between
VoIP
gateway and the
gatekeeper.
H.450.2
Call transfer supplementary service for
H.323
.
H.450.3
Call diversion supplementary service for
H.323
.
Hash, Hash
Algorithm
A hash algorithm is a one way function that operates on a message of arbitrary length to create a
fixed-length message digest used by cryptographic services to ensure its data integrity. MD5 has a
smaller digest and is considered to be slightly faster than
SHA-1
. Cisco uses both
SHA-1
and
MD5
hashes within our implementation of the
IPSec
framework. See also
encryption
,
HMAC
, and
VPN
.
headend
A firewall, concentrator, or other host that serves as the entry point into a private network for
VPN
client connections over the public network. See also
ISP
and
VPN
.
HMAC
A mechanism for message authentication using cryptographic hashes such as
SHA-1
and
MD5
.
host
The name for any device on a TCP/IP network that has an IP address. See also
network
and
node
.
host/network
An IP address and netmask used with other information to identify a single host or network subnet for
security appliance configuration, such as an address translation (
xlate
) or
ACE
.
HTTP
Hypertext Transfer Protocol. A protocol used by browsers and web servers to transfer files. When a
user views a web page, the browser can use HTTP to request and receive the files used by the web
page. HTTP transmissions are not encrypted.
HTTPS
Hypertext Transfer Protocol Secure. An
SSL
-encrypted version of HTTP.
I
IANA
Internet Assigned Number Authority. Assigns all port and protocol numbers for use on the
Internet
.
ICMP
Internet Control Message Protocol. Network-layer Internet protocol that reports errors and provides
other information relevant to IP packet processing.
IDS
Intrusion Detection System. A method of detecting malicious network activity by signatures and then
implementing a policy for that signature.
IETF
The Internet Engineering Task Force. A technical standards organization that develops
RFC
documents defining protocols for the
Internet
.
IGMP
Internet Group Management Protocol. IGMP is a protocol used by IPv4 systems to report IP
multicast
memberships to neighboring multicast routers.
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Страница 45: ...P A R T 1 Getting Started and General Information ...
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Страница 277: ...P A R T 2 Configuring the Firewall ...
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Страница 354: ...17 38 Cisco Security Appliance Command Line Configuration Guide OL 12172 03 Chapter 17 Configuring NAT NAT Examples ...
Страница 561: ...P A R T 3 Configuring VPN ...
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Страница 891: ...P A R T 4 System Administration ...
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