Scenario: 

Have two SSIDs configured on a Vigor2820 router: one WEP and the other WPA.
Computers associated with any SSID can access the internet OK.
Computers on one SSID cannot ping computers on another SSID.
Wireless LAN isolation not configured.
How can I connect all the systems to one LAN with multiple SSIDs?

 

Answer:

Using multiple SSIDs allows you to isolate one group of wireless network users from another group. You will need to place the users into the same SSID if you want them to see each other. Wireless LAN isolation will be prevent the wireless devices from seeing the wired PCs if enabled.

See also “Configuring Wireless Security in Vigor Routers