AAISP Data SIMS can be relayed on to your own L2TP Server, such as a FireBrick

FireBrick Config

On the WebUI, this is set under Tunnels, L2TP, Incoming L2TP connections.

<l2tp>
 <incoming name="MyL2TP" hostname="FireBrick" secret="myPassword" pppip="10.0.0.2" pppdns1="217.169.20.20" pppdns2="8.8.8.8" lcp-rate="25" lcp-timeout="240" tcp-mss-fix="true" radius="l2tp" log="ppp" log-debug="ppp">
 <match name="MySIM" graph="MySIM" calling-station-id="89442xxxxxx" remote-ip="10.0.0.4" comment="Change IP to one on your LAN"/>
</l2tp>

Change the pppip to be the IP you're using, ie the address if the FireBrick. The LCP rates are changed to be less

You will also need firewall filters, eg to allow trraffic out of the SIM:

      <rule name="L2TPOut" source-interface="l2tp"/>

AAISP Config

AAISP will set up a 'line' on the control pages for your SIM, you can request Staff to set up:

Target IP - IP (4 or 6) of your FireBrick
Host - The Hostname as set in your 'incoming' config, ie FireBrick in this case
secret - The secret as set in your incoming config, ie myPassword in this case