SnapGear 2.0.1 user manual Ntp, Appendix B Terminology

NAT	Network Address Translation. The translation of an IP address used on
	one network to an IP address on another network. Masquerading is
	one particular form of NAT.
Net mask	The way that computers know which part of a TCP/IP address refers to
	the network, and which part refers to the host range.
NTP	Network Time Protocol (NTP) used to synchronize clock times in a
	network of computers.
Oakley Group	See Diffie-Hellman Group or Oakley Group.
PAT	Port Address Translation. The translation of a port number used on
	one network to a port number on another network.
PEM, DER,	These are all certificate formats.
PCKS#12
PCKS#07
Perfect Forward	A property of systems such as Diffie-Hellman key exchange which use
Secrecy	a long-term key (such as the shared secret in IKE) and generate short-
	term keys as required. If an attacker who acquires the long-term key
	provably can neither read previous messages which he may have
	archived nor read future messages without performing additional
	successful attacksthen the system has PFS. The attacker needs the
	short-term keys in order to read the traffic and merely having the long-
	term key does not allow him to infer those. Of course, it may allow him
	to conduct another attack (such as man-in-the-middle) which gives him
	some short-term keys, but he does not automatically get them just by
	acquiring the long-term key.
Phase 1	Sets up a secure communications channel to establish the encrypted
	tunnel in IPSec.
Phase 2	Sets up the encrypted tunnel in IPSec.
PPP	Point-to-Point Protocol. A networking protocol for establishing simple
	links between two peers.
PPPoE	Point to Point Protocol over Ethernet. A protocol for connecting users
	on an Ethernet to the Internet using a common broadband medium
	(e.g. single DSL line, wireless device, cable modem, etc).
PPTP	Point to Point Tunneling Protocol. A protocol developed by Microsoft™
	that is popular for VPN applications. Although not considered as
	secure as IPSec, PPP is considered "good enough" technology.
	Microsoft has addressed many flaws in the original implementation.
Preshared secret	A common secret (passphrase) that is shared between the two parties.
Quick Mode	This Phase 2 keying mode automatically exchanges encryption and
	authentication keys that actually establishes the encrypted tunnel.
Rekeying	The process of renegotiating a new set of keys for encryption and
	authentication.
Road warrior	A remote machine with no fixed IP address.

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Appendix B – Terminology