used if the LAC requests authentication.
</LI>
+<LI><B>l2tp_mtu</B> (int)<BR>
+MTU of interface for L2TP traffic (default: 1500). Used to set link
+MRU and adjust TCP MSS.
+</LI>
+
<LI><B>ppp_restart_time</B> (int)<BR>
<B>ppp_max_configure</B> (int)<BR>
<B>ppp_max_failure</B> (int)<BR>