This glossary contains industry standard and City specific IT terminology. The glossary
should be consulted when policy, issue papers, etc. are drafted to ensure consistent use of terms across the City.
Virtual Private Network
Virtual Private Network - VPN
A Virtual Private Network - or VPN, is a network which emulates a private
network, although runs over public network lines and infrastructure. Using
specialist hardware and software, a VPN may be established running over the
Internet. The use of encryption and a 'tunnelling protocol' maintains privacy. Because public networks are used, the cost of a VPN costs a fraction of that
of a traditional private network.
A virus is a form of malicious code
and, as such it is potentially disruptive. It may also be transferred
unknowingly from one computer to another. The term Virus includes all sort of
variations on a theme, including the nastier variants of macro-viruses, Trojans,
and Worms, but, for convenience, all such programs are classed simply as
Viruses are a very real problem for both organization and individual computer
users. At the present time there are very few, if any, virus which affect large
computers, primarily because the programming languages which those systems use
are not the same as those used to write virus code. Viruses, therefore are a
problem primarily for users of PCs and servers.
As at January 2001, there were over 48,000 known viruses. Fortunately the
great majority of these are classed as 'rare' and usually appear only in virus
research centre files. However, that still leaves nearly 5,000 viruses, classed
as 'common', roaming the world's computer networks, so there is absolutely no
room for complacency.
They tend to fall into 3 groups:
- such as 'Resume' and 'Loveletter' which do real, sometimes
irrevocable, damage to a computer's system files, and the programs and data held
on the computer's storage media, as well as attempting to steal and transmit
user ID and password information
Childish; - such as 'Yeke', 'Hitchcock', 'Flip', and Diamond, which do
not, generally, corrupt or destroy data, programs, or boot records, but restrict
themselves to irritating activities such as displaying childish messages,
playing sounds, flipping the screen upside down, or displaying animated graphics
Ineffective - those, such as 'Bleah', which appear to do nothing at all
except reproduce themselves, or attach themselves to files in the system,
thereby clogging up the storage media with unnecessary clutter. Some of these
viruses are ineffective because of badly written code, - they should do
something, but the virus writer didn't get it quite right.
Within all types there are some which operate on the basis of a 'triggered
event' usually a date such as April 1st, or October 31st, or a time such 15:10
each day when the 'Tea Time' virus activates.
Organizations should maintain a 'virus diary' of known high risk dates/times
to ensure that anti-virus measures are in place as required.