There are many different intrusion detection and prevention systems out there
that use a variety of techniques. Open source or free options
Commercial products are also available from vendors such as
#4 Create wireless usage policies
Along with other general computer usage guidelines, you should have a
specific set of polices for Wi-Fi access which should at least include the following
- List devices authorized to access the wireless network: It's best
to deny all devices and explicitly allow each desired device by using MAC
address filtering on the network router. Though MAC addresses can be
spoofed, this provides reasonable control of which devices employees are
using on the network. A hard copy of all approved devices and their details
should be kept to compare against when monitoring the network and for
inputting into intrusion detection systems.
- List of personnel authorized with Wi-Fi access to the network:
This could be regulated when using 802.1X authentication (WPA/WPA2-Enterprise)
by only creating accounts in the RADIUS server for those who need Wi-Fi
access. If 802.1X authentication is also being used on wired side, you
should be able to specify whether users receive wired and/or wireless access
by modifying the Active Directory or using authorization policies on the
RADIUS server itself.
- Rules on setting up wireless routers or APs: For example, that
only the IT department can set up more APs, so employees don't just plug in
an AP from home to extend the signal. An internal rule for IT department might cover defining acceptable equipment models and configuration.
- Rules on using Wi-Fi hotspots or connecting to home networks with
company devices: Since the data on a device or laptop can be compromised
and the Internet activity be monitored on unsecured wireless networks, you
may want to limit Wi-Fi connections to only the company network. This could
be controlled by imposing network filters with the Network Shell (netsh)
utility in Windows. Alternatively, you could require a VPN connection back
to the company network to at least protect the Internet activity and to
remotely access files.
#5 Use SSL or IPsec on top of Wi-Fi encryption
Though you might be using the latest and greatest Wi-Fi encryption (on Layer
2 of the OSI model), consider implementing another encryption mechanism, such as
IPSec (on Layer 3 of the OSI model). In addition to providing double encryption
on the wireless side, it can secure the wired communication too. This would
prevent eavesdropping from employees or outsiders tapping into an ethernet port.
Eric Geier is the the author of many networking and computing
books for brands like For Dummies and Cisco Press.