编译出来的固件局域网里的电脑无法使用pptp

[thankeyes]

编译出来的固件局域网里的电脑无法使用pptp(已经装了kmod-nf-nathelper-extra 和 kmod-nf-nathelper)
局域网电脑一连PPTP,kernel显示
nf_conntrack: default automatic helper assignment has been turned off for security reasons and CT-based firewall rule not found. Use the iptables CT target to attach helpers instead
.