B C D
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H I J
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Q R S
T U V
W X Y
- User Agent. An OSI
application process that represents a human user or
organization in the X.400 Message Handling System.
Creates, submits, and takes delivery of messages on
the user's behalf. [Source: RFC1208]
- Unsolicited Bulk Email.
- Unsolicited Commercial
- Universities and
Colleges Information Systems Association, with several
subgroups, including UCISA-NG, the Networking Group
(which is an Affiliated Group of the JANET National
- See: User Datagram
- University for industry,
not strictly a University, nor for Industry.
- UHI Network
- University of Highlands
and Islands Network.
- the UK Education and
Research Networking Association; funded by the Joint
Information Systems Committee of the Higher Education
Funding Councils and others to manage the academic
network and its developments. Formerly the JNT.
- University of London
Computer Centre, CCNA of various networking
- An address which only
one host will recognize. See also: broadcast,
multicast. [Source: RFC1983]
- Uniform Resource
- A URL is a compact (most
of the time) string representation for a resource
available on the Internet. URLs are primarily used to
retrieve information using WWW. The syntax and
semantics for URLs are defined in RFC
1738. See also: World Wide Web. [Source: RFC1983]
- Universal Time
- This is Greenwich Mean
Time. [Source: MALAMUD]
- UNIX-to-UNIX CoPy (UUCP)
- This was initially a
program run under the UNIX operating system that
allowed one UNIX system to send files to another UNIX
system via dial-up phone lines. Today, the term is
more commonly used to describe the large international
network which uses the UUCP protocol to pass news and
electronic mail. See also: Electronic Mail, Usenet.
- Unrouteable Address
- Certain ranges of IP
addresses are designated in RFC
1918 as exclusively for internal use. These are
10.0.0.0 to 10.255.255.255, 172.16.0.0 to
172.16.255.255, and 192.168.0.0 to 192.168.255.255. A
correctly configured router will not allow packets
from any of these addresses through to the Internet.
The only way that information can pass between hosts
with any of these IP addresses and the outside world
is to have a device (typically a firewall) that
translates between these internal addresses and a
specific collection of IP addresses that are assigned
in the normal way. The internal IP addresses can be
safely re-used in many such locations. See also:
Network Address Translation, IP Address.
- urban legend
- A story, which may have
started with a grain of truth, that has been
embroidered and retold until it has passed into the
realm of myth. It is an interesting phenonmenon that
these stories get spread so far, so fast and so often.
Urban legends never die, they just end up on the
Internet! Some legends that periodically make their
rounds include "The Infamous Modem Tax,"
"Craig Shergold/Brain Tumor/Get Well Cards,"
and "The $250 Cookie Recipe". [Source:
- See: Uniform Resource
- A collection of
thousands of topically named newsgroups, the computers
which run the protocols, and the people who read and
submit Usenet news. Not all Internet hosts subscribe
to Usenet and not all Usenet hosts are on the
Internet. See also: Network News Transfer Protocol,
UNIX-to-UNIX CoPy. [Source: NWNET]
- User Datagram
- An Internet Standard
transport layer protocol defined in STD 6, RFC
768. It is a connectionless protocol which adds a
level of reliability and multiplexing to IP. See also:
connectionless, Transmission Control Protocol.
- See: Universal Time
- See: UNIX-to-UNIX CoPy
- A program which reverses
the effect of uuencode. See also: uuencode. [Source:
- A program which
reversibly converts a binary file in ASCII. It is used
to send binary files via email, which generally does
not allow (or garbles) the transmission of binary
information. The original binary can be restored with
uudecode. The encoding process generally creates an
ASCII file larger than the original binary, so
compressing the binary before running uuencode is
highly recommended. [Source: RFC1983]
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