Zyxel P-660HN-T1A Router Manual PDF (Setup & Configuration Guide)

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several intermediate rate steps between the maximum and minimum data rates.

The IEEE 802.11g data rate and modulation are as follows:

Wireless Security Overview

Wireless security is vital to your network to protect wireless communication

between wireless clients, access points and the wired network.

Wireless security methods available on the ZyXEL Device are data encryption,

wireless client authentication, restricting access by device MAC address and hiding

the ZyXEL Device identity.

The following figure shows the relative effectiveness of these wireless security

methods available on your ZyXEL Device.

Note: You must enable the same wireless security settings on the ZyXEL Device and

on all wireless clients that you want to associate with it.

Table 110

IEEE 802.11g

DATA RATE

(MBPS)

MODULATION

1

DBPSK (Differential Binary Phase Shift Keyed)

2

DQPSK (Differential Quadrature Phase Shift Keying)

5.5 / 11

CCK (Complementary Code Keying)

6/9/12/18/24/36/

48/54

OFDM (Orthogonal Frequency Division Multiplexing)

Table 111

Wireless Security Levels

SECURITY

LEVEL

SECURITY TYPE

Least

Secure

Most Secure

Unique SSID (Default)

Unique SSID with Hide SSID Enabled

MAC Address Filtering

WEP Encryption

IEEE802.1x EAP with RADIUS Server

Authentication

Wi-Fi Protected Access (WPA)

WPA2

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IEEE 802.1x

In June 2001, the IEEE 802.1x standard was designed to extend the features of

IEEE 802.11 to support extended authentication as well as providing additional

accounting and control features. It is supported by Windows XP and a number of

network devices. Some advantages of IEEE 802.1x are:

•

User based identification that allows for roaming.

•

Support for RADIUS (Remote Authentication Dial In User Service, RFC 2138,

2139) for centralized user profile and accounting management on a network

RADIUS server.

•

Support for EAP (Extensible Authentication Protocol, RFC 2486) that allows

additional authentication methods to be deployed with no changes to the access

point or the wireless clients.

RADIUS

RADIUS is based on a client-server model that supports authentication,

authorization and accounting. The access point is the client and the server is the

RADIUS server. The RADIUS server handles the following tasks:

• Authentication

Determines the identity of the users.

• Authorization

Determines the network services available to authenticated users once they are

connected to the network.

• Accounting

Keeps track of the client’s network activity.

RADIUS is a simple package exchange in which your AP acts as a message relay

between the wireless client and the network RADIUS server.

Types of RADIUS Messages

The following types of RADIUS messages are exchanged between the access point

and the RADIUS server for user authentication:

• Access-Request

Sent by an access point requesting authentication.

• Access-Reject

Sent by a RADIUS server rejecting access.

• Access-Accept

Sent by a RADIUS server allowing access.

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• Access-Challenge

Sent by a RADIUS server requesting more information in order to allow access.

The access point sends a proper response from the user and then sends another

Access-Request message.

The following types of RADIUS messages are exchanged between the access point

and the RADIUS server for user accounting:

• Accounting-Request

Sent by the access point requesting accounting.

• Accounting-Response

Sent by the RADIUS server to indicate that it has started or stopped accounting.

In order to ensure network security, the access point and the RADIUS server use a

shared secret key, which is a password, they both know. The key is not sent over

the network. In addition to the shared key, password information exchanged is

also encrypted to protect the network from unauthorized access.

Types of EAP Authentication

This section discusses some popular authentication types: EAP-MD5, EAP-TLS,

EAP-TTLS, PEAP and LEAP. Your wireless LAN device may not support all

authentication types.

EAP (Extensible Authentication Protocol) is an authentication protocol that runs on

top of the IEEE 802.1x transport mechanism in order to support multiple types of

user authentication. By using EAP to interact with an EAP-compatible RADIUS

server, an access point helps a wireless station and a RADIUS server perform

authentication.

The type of authentication you use depends on the RADIUS server and an

intermediary AP(s) that supports IEEE 802.1x. .

For EAP-TLS authentication type, you must first have a wired connection to the

network and obtain the certificate(s) from a certificate authority (CA). A certificate

(also called digital IDs) can be used to authenticate users and a CA issues

certificates and guarantees the identity of each certificate owner.

EAP-MD5 (Message-Digest Algorithm 5)

MD5 authentication is the simplest one-way authentication method. The

authentication server sends a challenge to the wireless client. The wireless client

‘proves’ that it knows the password by encrypting the password with the challenge

and sends back the information. Password is not sent in plain text.

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However, MD5 authentication has some weaknesses. Since the authentication

server needs to get the plaintext passwords, the passwords must be stored. Thus

someone other than the authentication server may access the password file. In

addition, it is possible to impersonate an authentication server as MD5

authentication method does not perform mutual authentication. Finally, MD5

authentication method does not support data encryption with dynamic session

key. You must configure WEP encryption keys for data encryption.

EAP-TLS (Transport Layer Security)

With EAP-TLS, digital certifications are needed by both the server and the wireless

clients for mutual authentication. The server presents a certificate to the client.

After validating the identity of the server, the client sends a different certificate to

the server. The exchange of certificates is done in the open before a secured

tunnel is created. This makes user identity vulnerable to passive attacks. A digital

certificate is an electronic ID card that authenticates the sender’s identity.

However, to implement EAP-TLS, you need a Certificate Authority (CA) to handle

certificates, which imposes a management overhead.

EAP-TTLS (Tunneled Transport Layer Service)

EAP-TTLS is an extension of the EAP-TLS authentication that uses certificates for

only the server-side authentications to establish a secure connection. Client

authentication is then done by sending username and password through the

secure connection, thus client identity is protected. For client authentication, EAP-

TTLS supports EAP methods and legacy authentication methods such as PAP,

CHAP, MS-CHAP and MS-CHAP v2.

PEAP (Protected EAP)

Like EAP-TTLS, server-side certificate authentication is used to establish a secure

connection, then use simple username and password methods through the

secured connection to authenticate the clients, thus hiding client identity.

However, PEAP only supports EAP methods, such as EAP-MD5, EAP-MSCHAPv2

and EAP-GTC (EAP-Generic Token Card), for client authentication. EAP-GTC is

implemented only by Cisco.

LEAP

LEAP (Lightweight Extensible Authentication Protocol) is a Cisco implementation of

IEEE 802.1x.

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Dynamic WEP Key Exchange

The AP maps a unique key that is generated with the RADIUS server. This key

expires when the wireless connection times out, disconnects or reauthentication

times out. A new WEP key is generated each time reauthentication is performed.

If this feature is enabled, it is not necessary to configure a default encryption key

in the wireless security configuration screen. You may still configure and store

keys, but they will not be used while dynamic WEP is enabled.

Note: EAP-MD5 cannot be used with Dynamic WEP Key Exchange

For added security, certificate-based authentications (EAP-TLS, EAP-TTLS and

PEAP) use dynamic keys for data encryption. They are often deployed in corporate

environments, but for public deployment, a simple user name and password pair

is more practical. The following table is a comparison of the features of

authentication types.

WPA and WPA2

Wi-Fi Protected Access (WPA) is a subset of the IEEE 802.11i standard. WPA2

(IEEE 802.11i) is a wireless security standard that defines stronger encryption,

authentication and key management than WPA.

Key differences between WPA or WPA2 and WEP are improved data encryption and

user authentication.

If both an AP and the wireless clients support WPA2 and you have an external

RADIUS server, use WPA2 for stronger data encryption. If you don't have an

external RADIUS server, you should use WPA2-PSK (WPA2-Pre-Shared Key) that

only requires a single (identical) password entered into each access point, wireless

gateway and wireless client. As long as the passwords match, a wireless client will

be granted access to a WLAN.

Table 112

Comparison of EAP Authentication Types

EAP-MD5

EAP-TLS

EAP-TTLS

PEAP

LEAP

Mutual Authentication

No

Yes

Certificate – Client

No

Yes

Optional

No

Certificate – Server

No

Yes

No

Dynamic Key Exchange

No

Yes

Credential Integrity

None

Strong

Moderate

Deployment Difficulty

Easy

Hard

Moderate

Client Identity

Protection

No

Yes

No

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