On the WebUI, this is set under Tunnels, [[L2TP]], Incoming [[L2TP]] connections, and basic XML example is as below:
[[File:SIMtoL2TP-FireBrick1.png|none|frame|FireBrick L2TP screenshot]]
*lpc-rate/timeout - used for graphs - we don't need to poll as often as the actual LCPs are not answered by the SIM, but by the mobile network. Basically latency on the graphs for SIMs should be ignored.
[[File:SIMtoL2TP-FireBrick2.png|frame|100px|FireBrick L2TP individual sessions screenshot]]
The match settings are to match individual SIMs when the connect in, and thus giving them their own IP address etc.