NETGEAR WGT624 Router Manual PDF (Setup & Configuration Guide)

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Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3

Wireless Networking Basics

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Temporal Key Integrity Protocol (TKIP)

WPA uses TKIP to provide important data encryption enhancements including a per-packet key

mixing function, a message integrity check (MIC) named Michael, an extended initialization

vector (IV) with sequencing rules, and a re-keying mechanism. TKIP also provides for the

following:

•

The verification of the security configuration after the encryption keys are determined.

•

The synchronized changing of the unicast encryption key for each frame.

•

The determination of a unique starting unicast encryption key for each preshared key

authentication.

Michael

With 802.11 and WEP, data integrity is provided by a 32-bit

integrity check value

(ICV) that is

appended to the 802.11 payload and encrypted with WEP. Although the ICV is encrypted, you can

use cryptanalysis to change bits in the encrypted payload and update the encrypted ICV without

being detected by the receiver.

With WPA, a method known as

Michael

specifies a new algorithm that calculates an 8-byte

message integrity check (MIC) using the calculation facilities available on existing wireless

devices. The MIC is placed between the data portion of the IEEE 802.11 frame and the 4-byte ICV.

The MIC field is encrypted together with the frame data and the ICV.

Michael also provides replay protection. A new frame counter in the IEEE 802.11 frame is used to

prevent replay attacks.

AES Support for WPA2

One of the encryption methods supported by WPA2 is the advanced encryption standard (AES),

although AES support will not be required initially for Wi-Fi certification. This is viewed as the

optimal choice for security conscience organizations, but the problem with AES is that it requires a

fundamental redesign of the NIC’s hardware in both the station and the access point. TKIP is a

pragmatic compromise that allows organizations to deploy better security while AES capable

equipment is being designed, manufactured, and incrementally deployed.

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Is WPA/WPA2 Perfect?

WPA/WPA2 is not without its vulnerabilities. Specifically, it is susceptible to denial of service

(DoS) attacks. If the access point receives two data packets that fail the message integrity code

(MIC) within 60 seconds of each other, then the network is under an active attack, and as a result,

the access point employs counter measures, which include disassociating each station using the

access point. This prevents an attacker from gleaning information about the encryption key and

alerts administrators, but it also causes users to lose network connectivity for 60 seconds. More

than anything else, this may just prove that no single security tactic is completely invulnerable.

WPA/WPA2 is a definite step forward in WLAN security over WEP and has to be thought of as a

single part of an end-to-end network security strategy.

Product Support for WPA/WPA2

Starting in August, 2003, NETGEAR, Inc. wireless Wi-Fi certified products will support the WPA

standard. NETGEAR, Inc. wireless products that had their Wi-Fi certification approved before

August, 2003 will have one year to add WPA so as to maintain their Wi-Fi certification.

WPA/WPA2 requires software changes to the following:

•

Wireless access points

•

Wireless network adapters

•

Wireless client programs

Supporting a Mixture of WPA, WPA2, and WEP Wireless Clients is Discouraged

To support the gradual transition of WEP-based wireless networks to WPA/WPA2, a wireless AP

can support both WEP and WPA/WPA2 clients at the same time. During the association, the

wireless AP determines which clients use WEP and which clients use WPA/WPA2. The

disadvantage to supporting a mixture of WEP and WPA/WPA2 clients is that the global encryption

key is not dynamic. This is because WEP-based clients cannot support it. All other benefits to the

WPA clients, such as integrity, are maintained.

However, a mixed mode supporting WPA/WPA2 and non-WPA/WPA2 clients would offer

network security that is no better than that obtained with a non-WPA/WPA2 network, and thus this

mode of operation is discouraged.

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Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3

Wireless Networking Basics

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Changes to Wireless Access Points

Wireless access points must have their firmware updated to support the following:

•

The new WPA/WPA2 information element

To advertise their support of WPA/WPA2, wireless APs send the beacon frame with a new

802.11 WPA/WPA2 information element that contains the wireless AP's security configuration

(encryption algorithms and wireless security configuration information).

•

The WPA/WPA2 two-phase authentication

Open system, then 802.1x (EAP with RADIUS or preshared key).

•

TKIP

•

Michael

•

AES

(WPA2)

To upgrade your wireless access points to support WPA/WPA2, obtain a WPA/WPA2 firmware

update from your wireless AP vendor and upload it to your wireless AP.

Changes to Wireless Network Adapters

Wireless networking software in the adapter, and possibly in the OS or client application, must be

updated to support the following:

•

The new WPA/WPA2 information element

Wireless clients must be able to process the WPA/WPA2 information element and respond

with a specific security configuration.

•

The WPA/WPA2 two-phase authentication

Open system, then 802.1x supplicant (EAP or preshared key).

•

TKIP

•

Michael

•

AES

(WPA2)

To upgrade your wireless network adapters to support WPA/WPA2, obtain a WPA/WPA2 update

from your wireless network adapter vendor and update the wireless network adapter driver.

For Windows wireless clients, you must obtain an updated network adapter driver that supports

WPA. For wireless network adapter drivers that are compatible with Windows XP (Service Pack 1)

and Windows Server 2003, the updated network adapter driver must be able to pass the adapter's

WPA capabilities and security configuration to the Wireless Zero Configuration service.

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Microsoft has worked with many wireless vendors to embed the WPA driver update in the wireless

adapter driver. So, to update your Microsoft Windows wireless client, all you have to do is obtain

the new WPA/WPA2-compatible driver and install the driver.

Changes to Wireless Client Programs

Wireless client programs must be updated to permit the configuration of WPA/WPA2

authentication (and preshared key) and the new WPA/WPA2 encryption algorithms (TKIP and

AES).

To obtain the Microsoft WPA client program, visit the Microsoft Web site.

Note

: The Microsoft WPA2 client is still in beta.

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Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3

Glossary

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Glossary

Use the list below to find definitions for technical terms used in this manual.

802.11 Standard

802.11, or IEEE 802.11, is a type of radio technology used for wireless local area networks (WLANs). It is a

standard that has been developed by the IEEE (Institute of Electrical and Electronic Engineers),

http://standards.ieee.org

. The IEEE is an international organization that develops standards for hundreds of

electronic and electrical technologies. The organization uses a series of numbers, like the Dewey Decimal

system in libraries, to differentiate between the various technology families.

The 802 subgroup (of the IEEE) develops standards for local and wide area networks with the 802.11 section

reviewing and creating standards for wireless local area networks.

Wi-Fi , 802.11, is composed of several standards operating in different radio frequencies: 802.11b is a

standard for wireless LANs operating in the 2.4 GHz spectrum with a bandwidth of 11 Mbps; 802.11a is a

different standard for wireless LANs, and pertains to systems operating in the 5 GHz frequency range with a

bandwidth of 54 Mbps. Another standard, 802.11g, is for WLANS operating in the 2.4 GHz frequency but

with a bandwidth of 54 Mbps.

802.11a Standard

An IEEE specification for wireless networking that operates in the 5 GHz frequency range (5.15 GHz to

5.85 GHz) with a maximum 54 Mbps data transfer rate. The 5 GHz frequency band is not as crowded as the

2.4 GHz frequency, because the 802.11a specification offers more radio channels than the 802.11b. These

additional channels can help avoid radio and microwave interference.

802.11b Standard

International standard for wireless networking that operates in the 2.4 GHz frequency range (2.4 GHz to

2.4835 GHz) and provides a throughput of up to 11 Mbps. This is a very commonly used frequency.

Microwave ovens, cordless phones, medical and scientific equipment, as well as Bluetooth devices, all work

within the 2.4 GHz frequency band.

802.11d Standard

802.11d is an IEEE standard supplementary to the Media Access Control (MAC) layer in 802.11 to promote

worldwide use of 802.11 WLANs. It will allow access points to communicate information on the

permissible radio channels with acceptable power levels for client devices. The devices will automatically

adjust based on geographic requirements.

The purpose of 11d is to add features and restrictions to allow WLANs to operate within the rules of these

countries. Equipment manufacturers do not want to produce a wide variety of country-specific products and

users that travel do not want a bag full of country-specific WLAN PC cards. The outcome will be

country-specific firmware solutions.

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