Protect Your Computers against Viruses
The first step towards virus protection is to install
anti-virus software. Typically, you should install the anti-virus software
in the mail server first, as that is where most viruses come these days.
Virus software installed on each computer in the network is a little more
controversial. Virus software tends to be more or less intrusive. Some
anti-virus software will constantly monitor all files. However, users
tend to complain about reduced performance as the hard disk gets scanned.
Other software will only scan when you tell it to, but such software is
of little use in practice in my opinion. No-one will scan nearly as often as
If you use anti-virus software, be sure to update the virus database
definitions frequently. Some anti-virus scanners will do this automatically
if they have a fixed line to the Internet. You should update at least daily
to be reasonably protected. New viruses typically spread the most within the
first couple of days.
Virus scanners will only do part of the job, though. New viruses
constantly show up, and no matter how clever the anti-virus software is, it
probably won't recognize most new viruses.
It is important to keep updating your application programs with new
patches and service packs as they become available. This is especially
important with Microsoft products. Not necessarily because Microsoft
software is any buggier than other programs, but because Microsoft programs
are widely used. That makes them popular with the virus makers who use bugs
in them to spread viruses. In fact, one way to avoid viruses is to use
alternatives to Microsoft products whenever possible (of course, that may
introduce other problems instead).
Some viruses use bugs and security flaws in Internet Explorer to spread.
By default Internet Explorer is configured in a way that is relatively
unsafe. By selecting Internet Options from within Internet Explorer and then
clicking on the Security tab, you can change the security settings.
In the so called "Internet Zone", a security setting of High is really
warranted. Unfortunately, that will make it impossible to view certain
content - especially Adobe Acrobat documents. I have modified my settings so
that I get prompted whenever Internet Explorer wants to do anything
potentially dangerous. If I know I am trying to read an Adobe document I
click yes, otherwise I click no. I get quite a lot of prompts, though and it
is a bit annoying.
The thing about Internet Explorer is that it is used not only when you
are browsing the Internet, but also when you receive an e-mail containing
HTML or links to HTML content. It is possible to send an e-mail that will
automatically download and run a virus when you open it. Tightened security
settings could help you out here.
Macro viruses are most common in Microsoft Office documents. Again, this
is not because Microsoft Office is the only software that can be infected
but because everyone is using it. You can make Office warn you about
documents containing macros. It is good practice to do that, although many
users will just ignore the warnings as they can become to frequent.
final advice is to install launch protection
software on every computer. It will not protect you against macro
viruses, but you will be safe from most other types. The combination of
launch protection and a good anti-virus scanner in the
mail server provides pretty good protection.