On the iOS device, navigate to the Settings app, to General, and then to the VPN menu.
Change the Type to L2TP and tap Back.
Fill in the information from your Cipafilter. After all of your information is filled out, tap Done. Server: DNS name or public IP of the Cipafilter. Account: Username created on the Management Users page of the Cipafilter (VPN checkbox required). Secret: Pre-Shared Key on the VPN page of the Cipafilter.
The VPN page will display your new connection. Toggle the Status 'on', and if you entered your settings correctly, it will say "Connected."