Configuring a WLAN for Static WEP

Restrictions for Configuring Static WEP

  • The OEAP 600 series does not support fast roaming for clients. Dual mode voice clients will experience reduced call quality when they roam between the two spectrums on OEAP602 access point. We recommend that you configure voice devices to only connect on one band, either 2.4 GHz or 5 GHz.

  • The controller software supports CCX versions 1 through 5. CCX support is enabled automatically for every WLAN on the controller and cannot be disabled. The controller stores the CCX version of the client in its client database and uses it to limit client functionality. Clients must support CCXv4 or v5 in order to use CCKM. For more information about CCX, see the Configuring Cisco Client Extensions section.

  • In a unified architecture where multiple VLAN clients are supported for a WGB, you also need to configure encryption cipher suite and WEP keys globally, when the WEP encryption is enabled on the WGB. Otherwise, multicast traffic for wired VLAN clients fail.

WLAN for Static WEP

You can configure up to four WLANs to support static WEP keys. Follow these guidelines when configuring a WLAN for static WEP:

  • When you configure static WEP as the Layer 2 security policy, no other security policies can be specified. That is, you cannot configure web authentication. However, when you configure static WEP as the Layer 2 security policy, you can configure web authentication.


Note

Dynamic WEP encryption method is not supported. The last release to support this method was Release 7.0 (7.0.240.0 and later 7.0 releases).

WPA1 and WPA2

Wi-Fi Protected Access (WPA or WPA1) and WPA2 are standards-based security solutions from the Wi-Fi Alliance that provide data protection and access control for wireless LAN systems. WPA1 is compatible with the IEEE 802.11i standard but was implemented prior to the standard’s ratification; WPA2 is the Wi-Fi Alliance's implementation of the ratified IEEE 802.11i standard.


Note

WPA1 is deprecated. It may not be configured by itself, but only enabled if WPA2/CCMP128 (AES) is also enabled. WPA2 is the default. WPA3 is the emerging standard.

These standards provide for an authentication method and a cipher management method. The authentication methods supported are: 802.1X (a.k.a WPA Enterprise) and PSK.

By default, WPA1 uses Temporal Key Integrity Protocol (TKIP) and message integrity check (MIC) for data protection while WPA2 uses the stronger Advanced Encryption Standard encryption algorithm using Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (AES-CCMP). Both WPA1 and WPA2 use 802.1X for authenticated key management by default. However, these options are also available:

  • 802.1X—The standard for wireless LAN security, as defined by IEEE, is called 802.1X for 802.11, or simply 802.1X. An access point that supports 802.1X acts as the interface between a wireless client and an authentication server, such as a RADIUS server, to which the access point communicates over the wired network. If 802.1X is selected, only 802.1X clients are supported.

    In the 802.1X(Enterprise) authentication method, the clients use EAP (extensible authentication protocol) to authenticate with an authentication server. The authentication server can be an external RADIUS or LDAP server, or a local auth server running within the controller.

    To speed up roaming, a fast secure roaming method may optionally be deployed to bypass the authentication and key exchange phases.

  • PSK—When you choose PSK (also known as WPA preshared key or WPA passphrase), you need to configure a preshared key (or a passphrase). This key is used as the pairwise master key (PMK) between the clients and the authentication server.

  • CCKM—Cisco Centralized Key Management (CCKM) uses a fast rekeying technique that enables clients to roam from one access point to another without going through the controller, typically in under 150 milliseconds (ms). CCKM reduces the time required by the client to mutually authenticate with the new access point and derive a new session key during reassociation. CCKM fast secure roaming ensures that there is no perceptible delay in time-sensitive applications such as wireless Voice over IP (VoIP), enterprise resource planning (ERP), or Citrix-based solutions. CCKM is a CCXv4-compliant feature. If CCKM is selected, only CCKM clients are supported.

    When CCKM is enabled, the behavior of access points differs from the controller's for fast roaming in the following ways:

    • If an association request sent by a client has CCKM enabled in a Robust Secure Network Information Element (RSN IE) but CCKM IE is not encoded and only PMKID is encoded in RSN IE, then the controller does not do a full authentication. Instead, the controller validates the PMKID and does a four-way handshake.

    • If an association request sent by a client has CCKM enabled in RSN IE but CCKM IE is not encoded and only PMKID is encoded in RSN IE, then AP does a full authentication. The access point does not use PMKID sent with the association request when CCKM is enabled in RSN IE.

  • 802.1X+CCKM—During normal operation, 802.1X-enabled clients mutually authenticate with a new access point by performing a complete 802.1X authentication, including communication with the main RADIUS server. However, when you configure your WLAN for 802.1X and CCKM fast secure roaming, CCKM-enabled clients securely roam from one access point to another without the need to reauthenticate to the RADIUS server. 802.1X+CCKM is considered optional CCKM because both CCKM and non-CCKM clients are supported when this option is selected.

On a single WLAN, you can allow WPA1, WPA2, and 802.1X/PSK/CCKM/802.1X+CCKM clients to join. All of the access points on such a WLAN advertise WPA1, WPA2, and 802.1X/PSK/CCKM/
802.1X+CCKM information elements in their beacons and probe responses. When you enable WPA1 and/or WPA2, you can also enable one or two ciphers, or cryptographic algorithms, designed to protect data traffic. Specifically, you can enable AES and/or TKIP data encryption for WPA1 and/or WPA2. TKIP is the default value for WPA1, and AES is the default value for WPA2.

This section contains the following subsections:

Configuring WPA1+WPA2

Configuring WPA1+WPA2 (GUI)

Procedure

Step 1

Choose WLANs to open the WLANs page.

Step 2

Click the ID number of the desired WLAN to open the WLANs > Edit page.

Step 3

Choose the Security and Layer 2 tabs to open the WLANs > Edit (Security > Layer 2) page.

Step 4

Choose WPA+WPA2 from the Layer 2 Security drop-down list.

Step 5

Under WPA+WPA2 Parameters, select the WPA Policy check box to enable WPA1, select the WPA2 Policy check box to enable WPA2, or select both check boxes to enable both WPA1 and WPA2.

Note 

By default, WPA2 with CCMP128 is enabled. Optionally, WPA1 with CCMP128 and/or TKIP may be enabled, but WPA1 may not be configured with WPA2 disabled.

Note 

Configure CCMP128(AES) for compatibility with greatest range of clients. Optionally, more secure ciphers (CCMP256, GCMP128, GCMP256) may be selected for greater security with recently released clients.

If using 802.1X (Enterprise) authentication, select 802.1X-SHA1 for compatibility with greatest range of clients. Or optionally, select 802.1X-SHA2 for use with recently released clients.

Step 6

Select the AES check box to enable AES data encryption or the TKIP check box to enable TKIP data encryption for WPA1, WPA2, or both. The default values are TKIP for WPA1 and AES for WPA2.

Step 7

Choose one of the following key management methods from the Auth Key Mgmt drop-down list: 802.1X, CCKM, PSK, or 802.1X+CCKM.

Note 

Cisco OEAP 600 does not support CCKM. You must choose either 802.1X or PSK.

Note 

For Cisco OEAP 600, the TKIP and AES security encryption settings must be identical for WPA and WPA2.

Step 8

If you chose PSK, choose ASCII or HEX from the PSK Format drop-down list and then enter a preshared key in the blank text box. WPA preshared keys must contain 8 to 63 ASCII text characters or 64 hexadecimal characters.

Note 
The PSK parameter is a set-only parameter. The value set for the PSK key is not visible to the user for security reasons. For example, if you selected HEX as the key format when setting the PSK key, and later when you view the parameters of this WLAN, the value shown is the default value. The default is ASCII.
Step 9

Save the configuration.

Configuring WPA1+WPA2 (CLI)

Procedure

Step 1

Disable the WLAN by entering this command:

config wlan disable wlan_id

Step 2

Enable or disable WPA for the WLAN by entering this command:

config wlan security wpa {enable | disable} wlan_id

Step 3

Enable or disable WPA1 for the WLAN by entering this command:

config wlan security wpa wpa1 {enable | disable} wlan_id

Step 4

Enable or disable WPA2 for the WLAN by entering this command:

config wlan security wpa wpa2 {enable | disable} wlan_id

Step 5

Enable or disable AES or TKIP data encryption for WPA1 or WPA2 by entering one of these commands:

  • config wlan security wpa wpa1 ciphers {aes | tkip} {enable | disable} wlan_id

  • config wlan security wpa wpa2 ciphers {aes | tkip} {enable | disable} wlan_id

The default values are TKIP for WPA1 and AES for WPA2.

Note 
You can enable or disable TKIP encryption only using the CLI. Configuring TKIP encryption is not supported in GUI.

When you have VLAN configuration on WGB, you need to configure the encryption cipher mode and keys for a particular VLAN, for example, encryption vlan 80 mode ciphers tkip . Then, you need configure the encryption cipher mode globally on the multicast interface by entering the following command: encryption mode ciphers tkip .

Step 6

Enable or disable 802.1X, PSK, or CCKM authenticated key management by entering this command:

config wlan security wpa akm {802.1X | psk | cckm} {enable | disable} wlan_id

The default value is 802.1X.
Step 7

If you enabled PSK in Step 6, enter this command to specify a preshared key:

config wlan security wpa akm psk set-key {ascii | hex} psk-key wlan_id

WPA preshared keys must contain 8 to 63 ASCII text characters or 64 hexadecimal characters.

Step 8

Enable or disable authentication key management suite for fast transition by entering this command:

config wlan security wpa akm ft {802.1X | psk} {enable | disable} wlan_id

Note 
You can now choose between the PSK and the fast transition PSK as the AKM suite.
Step 9

Enable or disable randomization of group temporal keys (GTK) between AP and clients by entering this command:

config wlan security wpa gtk-random {enable | disable} wlan_id

Step 10

If you enabled WPA2 with 802.1X authenticated key management or WPA1 or WPA2 with CCKM authenticated key management, the PMK cache lifetime timer is used to trigger reauthentication with the client when necessary. The timer is based on the timeout value received from the AAA server or the WLAN session timeout setting. To see the amount of time remaining before the timer expires, enter this command:

show pmk-cache all

If you enabled WPA2 with 802.1X authenticated key management, the controller supports both opportunistic PMKID caching and sticky (or non-opportunistic) PMKID caching. In sticky PMKID caching (SKC), the client stores multiple PMKIDs, a different PMKID for every AP it associates with. Opportunistic PMKID caching (OKC) stores only one PMKID per client. By default, the controller supports OKC.

Step 11

Enable the WLAN by entering this command:

config wlan enable wlan_id

Step 12

Save your settings by entering this command:

save config