Dell SonicWALL GX250 Manual page 147

1. Click VPN on the left side of the browser window and then click the Configure
tab at the top of the window.
2. Select IKE using pre-shared secret from the IPSec Keying Mode menu.
3. Check the Require XAUTH/RADIUS (only allows VPN clients) checkbox. This
forces inbound VPN clients to connect to this Security Association to authenticate
to a RADIUS server.
4. Configure the Security Association as specified in the IKE Configuration for
the VPN Client section.
Note: Only SonicWALL VPN Clients may authenticate to a RADIUS server. Users
tunneling from another VPN gateway, such a second SonicWALL, is not able to
complete the VPN tunnel if the Require XAUTH/RADIUS checkbox is checked.
SonicWALL Internet Security Appliance Guide Page 147