PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

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359
Physical Security
The security threats we have considered so far relate to intangibles such as software, but
you should not neglect the physical security of your system.You need air conditioning
and protection against fire, people (both the clumsy and the criminal), power failure, and
network failure.
Your system should be locked up securely. Depending on the scale of your operation,
your approach could be a room, a cage, or a cupboard. Personnel who do not need
access to this machine room should not have it. Unauthorized people might deliberately
or accidentally unplug cables or attempt to bypass security mechanisms using a bootable
disk.
Water sprinklers can do as much damage to electronics as a fire. In the past, halon fire
suppression systems were used to avoid this problem.The production of halon is now
banned under the Montreal Protocol on Substances That Deplete the Ozone Layer, so
new fire suppression systems must use other, less harmful, alternatives such as argon or
carbon dioxide.You can read more about this issue at http://www.epa.gov/Ozone/snap/
fire/qa.html.
Occasional brief power failures are a fact of life in most places. In locations with
harsh weather and above-ground wires, long failures occur regularly. If the continuous
operation of your systems is important to you, you should invest in an uninterruptible
power supply (UPS). A UPS that can power a single machine for up to 60 minutes costs
less than $200 (U.S.). Allowing for longer failures, or more equipment, can become
expensive. Long power failures really require a generator to run air conditioning as well
as computers.
Like power failures, network outages of minutes or hours are out of your control and
bound to occur occasionally. If your network is vital, it makes sense to have connections
to more than one Internet service provider. Having two connections costs more but
should mean that, in case of failure, you have reduced capacity rather than becoming
invisible.
These sorts of issues are some of the reasons you might like to consider co-locating
your machines at a dedicated facility. Although one medium-sized business might not be
able to justify a UPS that will run for more than a few minutes, multiple redundant network
connections, and fire suppression systems, a quality facility housing the machines of
a hundred similar businesses can.
Next
In Chapter 16, we take a further look at web application security.We look at who our
enemies are and how to defend ourselves against them; how to protect our servers, networks,
and code; and how to plan for disasters.