Watchguard Firebox X1000 Reference Manual page 139

Reference Guide
IDSs that operate on network data flows are called network-based
IDSs.
IP (Internet Protocol)
A protocol used by the Internet that enables computers to
communicate over various physical media.
IP address host
The 32-bit address that identifies a host. Technically, a host is a
network device connected to the Internet. In common usage, a
host is a computer or some other device that has a unique IP
address. Computers with more than one IP address are known as
multihomed hosts.
IP fragment
An IP datagram that is actually part of a larger IP packet. IP
fragments are typically used when an IP packet is too large for the
physical media that the data must cross. For example, the IP
standard for Ethernet limits IP packets to about 1,500 bytes, but
the maximum IP packet size is 65,536 bytes. To send packets larger
than 1,500 bytes over an Ethernet, IP fragments must be used.
IP masquerading
See dynamic NAT.
IP options
Extensions to the Internet Protocol used mainly for debugging
and special applications on local networks. In general, there are
no legitimate uses of IP options over an Internet connection.
IP options attack
A method of gaining network access by using IP options.
IPSec (Internet Protocol Security)
An open-standard methodology of creating a secure tunnel
through the Internet, connecting two remote hosts or networks.
IPSec provides several encryption and authentication options to
maximize the security of the transmission over a public medium
such as the Internet.
IP spoofing
The act of inserting a false sender IP address into an Internet
transmission to gain unauthorized access to a computer system.
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