How to set up ufw rules for softether vpn?

http://blog.lincoln.hk/blog/2013/05/17/softether-on-vps-using-local-bridge I set softether referring above link. And I set an L2TP vpn.

My “ifconfig”

eth0 (I replaced my server ip with 1.2.3.4）

Link encap:Ethernet HWaddr fa:16:3e:3c:b0:a0 inet addr:1.2.3.4 Bcast:1.2.3.255 Mask:255.255.254.0 inet6 addr: fe80::f816:3eff:fe3c:b0a0/64 Scope:Link

lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host

tap_soft Link encap:Ethernet HWaddr 00:ac:ab:80:3c:c7 inet addr:10.10.10.10 Bcast:10.255.255.255 Mask:255.0.0.0 inet6 addr: fe80::2ac:abff:fe80:3cc7/64 Scope:Link

My dnsmasq.conf

interface=tap_soft dhcp-range=tap_soft,10.10.10.10,10.10.10.20,12h dhcp-option=tap_soft,3,10.10.10.10

My ufw setup

ufw default reject incoming ufw default allow outgoing ufw allow 500/udp ufw allow 4500/udp ufw allow 1701

I can’t connect to L2TP when I enable ufw. But it’s ok when ufw disabled.

Thanks!