Defending Against Attacks

A good defense is having a knowledgeable offense. This means that you
must look at every computing device, printing device, and networked
storage resource device on your network as a potential way in which
hackers can breach your system and gain access to important resources.

Each device on your network needs to be examined in terms of security
including:

• 
  Networked printers
• 
  Networked attached storage (NAS) boxes
• 
  Wireless routers
• 
  802.11b servers
• 
  Web servers
• 
  File servers
• 
  Network fax servers

The first step for any networked device is to read the manual and
determine how well you can execute the security settings so that very
few people know the access codes, logins, and passwords to access the
device. In this way, even if someone could see the unit on the network, it
would be difficult, if not impossible, to access it.

The most vital concept, of course, is to keep an eye on your internal
and external network access points. If you configure your wireless network
to accept network connections only from those network cards you
trust, then it would not be possible for someone to sit outside your building
and set his NIC card to promiscuous mode to try to access your network
resources.


In addition, always remember to assign at least some level of encryption
to your network traffic so that it becomes that much more difficult
for someone trying to break into your wireless network to decode your
information.


Taking steps to prevent hackers from eavesdropping on or accessing
your network is simple, but requires the time and patience to know
these settings exist and then to set them. The rule you should follow is
never to put any device on your wired network without knowing exactly
what types of inherent security features it offers to restrict access.
Most network printers, for example, can restrict themselves to functioning
only in a certain domain and being accessible only to specific
users. You should consider restricting access to network devices so that
only authorized users can attempt to use these valuable resources. If
someone can access a device on your wired network, you can be certain
that someone can access that same device on the WLAN too.

One last good measure is to set your network devices to keep a log of
all incoming network traffic, most especially traffic received from wireless
stations. If all else fails and you don’t know how you are being
hacked (or the hack is so subtle you don’t even realize anything is happening
until it is too late), you can use the information in these logs to
track down the culprits responsible for disrupting your wireless network.
Even if you can’t find the people responsible for destroying the
integrity of your WLAN, you can at least use this information to plug
the security hole in your wireless network so that hackers can no longer
exploit open pathways to different devices on your network.