Glossary
Multi-Tech RouteFinder RF650VPN User Guide
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IP Header
– The part of the IP packet that carries data used on packet routing. The size of this header is
20 bytes, but usually the IP options following this header are also calculated as header. The maximum
length of the header is 60 bytes. The header format is defined in RFC 791.
IP Packet
– A self-contained independent entity of data carrying sufficient information to be routed from
the source to the destination computer without relying on any earlier exchange between this source and
destination computer and the transporting network. The Internet Protocol (IP) is defined in RFC 791.
IP Payload
– The part of the IP packet that carries upper level application data.
IPSec (IP Security)
– A set of IETF standards that provide authentication and encryption for IP-based
and Internet-based VPNs.
Key
– A data string which, when combined with source data (a packet) using a special algorithm,
produces output that cannot be read without that specific key. Key data strings are typically 40 to 168 bits
in length.
Key Agreement
– A process used by two or more parties to agree upon a secret symmetric key.
Key Exchange
– A process used by two more parties to exchange keys in cryptosystems.
Key Generation
– The act or process of creating a key.
Key Management
– The various processes that deal with the creation, distribution, authentication, and
storage of keys.
Key Pair
– The full key information in a public-key cryptosystem; consists of the public key and private
key.
L2TP (Layer Two Tunnelling Protocol)
– A security protocol that facilitates the tunnelling of PPP
packets across an intervening network in a way that is highly-transparent to both end-users and
applications. L2TP is defined in IETF RFC 2661.
LILO (LInux LOader)
– LILO is a small program that sits on the master boot record of a hard drive or on
the boot sector of a partition. LILO is used to start the loading process of the Linux kernel. (There are
other programs that can also do this, such as grub. Most distributions / versions of Linux use LILO.) You
can set up lilo to require a password to start to load the Linux kernel, or you can set it up to require a
password if you want to pass any extra options to the Linux kernel before it starts loading.
Mapping
– Logically associating one set of values (such as addresses on one network) with values or
quantities on another set (such as devices on another network). Examples include name-address
mapping, inter-network route mapping, and DNAT port mapping. Name resolution (name to address
mapping) is another example.
Masquerading
– The concealing of internal network information (LAN) form the outside.
For example, the computer of a colleague with the IP address is inside a masked network. All the
computers inside his network are assigned one single, official IP address (i.e. if he starts an HTTP
request into the Internet, his IP address is replaced by the IP address of the external network card). This
way, the data packet entering the external network (Internet) contains no internal information. The answer
to the request is recognized by the firewall and diverted to the requesting computer.
MD5 (Message Digest 5)
– A one-way hashing algorithm that produces a 128-bit hash. computes a
secure, irreversible, cryptographically strong hash value for a document. The MD5 algorithm is
documented in IETF RFC 1321.
Message Digests
– Mathematical functions (aka, one-way hashes) that are easy to compute but nearly
impossible to reverse. The message digest serves as a "fingerprint" for data. As such, it is an element of
most data security mechanisms (e.g., Digital Signatures, SSL, etc.). The hashing function takes variable-
length data as input, performs a function on it, and generates a fixed-length hash value.
MPPE (Microsoft Point-to-Point Encryption)
– An encryption technology developed by Microsoft to
encrypt point-to-point links. The PPP conections can be over a VPN tunnel or over a dial-up line. MPPE
is a feature of Microsoft's MPPC scheme for compressing PPP packets. The MPPC algorithmwas
