Cisco: Broadcasting Multiple SSIDs

Businessman Configuring Multiple Wireless SSIDsBy default, service set identifiers (SSIDs) configured on a Cisco integrated services router are not broadcast. This means that if you want to configure a client to use the wireless network, you'll have to manually enter the SSID in the client configuration. This isn't a bad thing, but it is a tad inconvenient.

A quick note: there is no security benefit to not broadcasting the SSID. Whenever a client connects to the "hidden" network, the SSID is sent in cleartext and is easily captured.

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In order to broadcast the SSID, you need to add the guest-mode command to the SSID configuration. For example:

dot11 ssid EXAMPLESSID1
   vlan 9
   authentication open 
   guest-mode
!
interface Dot11Radio1
 no ip address
 !
 ssid EXAMPLESSID1
 !
 station-role root
!
interface Dot11Radio1.9
 encapsulation dot1Q 9
!

If you try to add another guest-mode SSID to the radio interface, you'll get the following error:

Dot11Radio1: Guest-ssid already existing on ssid EXAMPLESSID1

So, what needs to be done?

The key to multiple broadcast SSIDs is in the mbssid command. Simply change the guest-mode command to mbssid guest-mode and add mbssid to the interface configuration.

Here's an example configuration.

dot11 ssid EXAMPLESSID1
   vlan 9
   authentication open 
   mbssid guest-mode
!
dot11 ssid EXAMPLESSID2
   vlan 99
   authentication open 
   mbssid guest-mode
!
interface Dot11Radio1
 no ip address
 !
 ssid EXAMPLESSID1
 !
 ssid EXAMPLESSID2
 !
 mbssid
 station-role root
!
interface Dot11Radio1.9
 encapsulation dot1Q 9
!
interface Dot11Radio1.99
 encapsulation dot1Q 99
!

Obviously, this configuration isn't enough to get our wireless working, but it shows the basics of getting multiple SSIDs to broadcast in guest mode.

Photo by Emin Ozkan.

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