Fortinet FortiGate FortiGate-5001 Administration Manual page 378

Glossary
ESP, Encapsulated Security Protocol: An IPSec
security protocol that provides encapsulation of
encrypted data—IP packets are embedded in other IP
packets so that the originating source and destination
IP addresses cannot be seen on the Internet.
Ethernet: Can refer to the IEEE 802.3 signaling
protocol, or an Ethernet controller (also known as a
Media Access Controller or MAC).
external interface: The FortiGate interface that
connects to the Internet.
failover: A FortiGate unit taking over the processing of
network traffic for another unit in the cluster that
suffered a device or link failure.
failure: A hardware or software problem that causes a
FortiGate unit or a monitored interface to stop
processing network traffic.
FGCP, FortiGate Clustering Protocol: A protocol that
specifies how the FortiGate units in a cluster
communicate to keep the cluster operating.
FTP, File Transfer Protocol: A protocol used to
transfer files between computers that have different
operating systems.
gateway: A combination of hardware and layer-3
(network-layer) software that relays packets from one
network to another.
hash algorithm: A procedure that renders a text
message as a unique number.
HA virtual MAC address: When operating in HA
mode, all of the interfaces of the primary cluster unit
acquire the same HA virtual MAC address. All
communications with the cluster must use this MAC
address. The HA virtual MAC address is set according
to the group ID.
header: The part of a packet that includes the source
and destination address of the associated data. This
addressing information is used to route packets.
heartbeat: Also called FGCP heartbeat or HA
heartbeat. The heartbeat constantly communicates HA
status and synchronization information to make sure
that the cluster is operating properly.
heartbeat device: An ethernet network interface in a
cluster that is used by the FGCP for heartbeat
communications among cluster units.
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heartbeat failover: If an interface functioning as a
heartbeat device fails, the heartbeat is transferred to
another interface also configured as an HA heartbeat
device.
high availability: The ability that a cluster has to
maintain a connection when there is a device or link
failure. Another unit in the cluster takes over the
connection, without any loss of connectivity. To achieve
high availability, all FortiGate units in the cluster share
session and configuration information.
hop: The segment of packet transmission that occurs
between two routers. A packet may make several hops
as it travels to its destination.
host: A network entity that has an IP address.
HTTP, Hypertext Transmission Protocol: The
protocol used by the World Wide Web. HTTP defines
how messages are formatted and transmitted, and
what actions Web servers and browsers should take in
response to various commands.
HTTPS: The secure HTML protocol for transmitting
encrypted information to web servers using SSL. See
also SSL.
hub: A device where communication links are brought
together to exchange data between several computers.
ICMP, Internet Control Message Protocol: An IP
message control protocol that supports error
messages, test packets, and information messages
related to IP. This protocol is used by the ping
generator to send ICMP echo requests to a host.
IKE, Internet Key Exchange: A method of
automatically exchanging IPSec authentication and
encryption keys between two secure servers.
IMAP, Internet Message Access Protocol: An
Internet email protocol that allows access to an email
server from any IMAP-compatible browser.
internal interface: The FortiGate interface that
connects to an internal (private) network.
Internet: The network that encompasses the world. As
a generic term, it refers to any collection of
interdependent networks.
IP, Internet Protocol: The component of TCP/IP that
handles routing.
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