Draytek 2960 VPN

想問下各位師兄, 我想setup L2TP/IPSEC vpn server only, 點解如果我唔activate pptp 的話, 就唔可以用L2TP/IPSEC connect 去vpn server 呢?
因覺得pptp 冇咁安全,所以唔想activate pptp