- RADIUS
- Remote Authentication Dial-In user Service.
A standard for authentication and accounting, RADIUS is primarily used to
control dial-up access to PPP and other services.
The protocal was standardized in RFC
2058, the current implementation is defined in RFCs 2138 and 2139.
RADIUS uses UDP packets, older servers use ports 1645 and 1646,
the current standard is port 1812 for authentication and 1813 for accounting.
See also
TACACS.
- RAM
- Acronym for Random Access Memory, a form of
primary storage that allows direct read and write operations. RAM storage
is generally a very high-speed medium that requires constant power to avoid
data loss.
See also
ROM.
(rezidew)
- RARP
- Reverse ARP, a mechanism to match a
MAC address to the corresponding
IP address.
- RAS
- Remote Access Server.
Generally used to refer to NT services, RAS is similar to
NAS both terms describe specialized models of
terminal server
- RBL
- Realtime Blackhole List.
A list of open mail relays and rogue sites, maintained by Paul Vixie.
Subscribers to the RBL reject all mail and/or connection attempts from
RBL'd IP addresses, effectively cutting off irresponsible/incompetent domains
from the rest of the Internet. Subscription is completely voluntary, details
are at
http://maps.vix.com/rbl/.
- Regular Expression.
- Regular Expressions use
Meta Characters
to express variable parts of a pattern to be matched.
Regular Expression.
(rezidew)
- RFC
- Acronym for Request For Comment, these a broad range of notes
covering a variety of topics related to the Internet. RFCs are handled by the
IETF and are
archived
at several sites.
- RIP
- Router Information Protocol, a standard mechanism for exchanging
routes (paths) between
routers, this protocol is slowly being replaced
by OSPF. RIP is specified in
RFC
1058.
- RISC
- Reduced Instruction Set Computer. A
CPU based on a limited number of basic instructions,
systems using RISC result in larger binary files but overally faster
execution of each instruction.
- Rm
- The
Unix command.
to delete a file from a
directory.
- Rmdir
- The
Unix command.
to delete a directory.
- ROM
- Acronym for Read-Only Memory, ROM is used for
permanent storage, such as system
bootstrap routines.
See also
RAM.
(rezidew)
- Root
- 1: The 'base' or bottom of a system. e.g. the 'root directory' is the
lowest possible directory in a filesystem, and in
X11 the 'root window' is the background on which all
other windows are drawn.
2: In Unix, the user 'root' is the user that owns the system and has full
superuser power.
- Rot-13
- A simple form of encryption in which the letters A-M are transposed with
the letters L-Z, often used in
Usenet postings of offensive jokes to prevent people
from accidentally reading a disturbing message.
- ROTFL
- Shorthand for Rolling On the Floor Laughing.
See also:
IMHO,
TMK.
- Router
- A router is a special type of internet
host
that gateways (transfers) packets between two or more networks.
- Ruby
A scripting language influenced by
Perl and
Eiffel.
Ruby Home Page