ipsec

###connect to unbutu strongswan xl2tpd

emerge libreswan xl2tpd

/etc/ipsec.d/xxx.conf

conn xxx
    authby=secret
    pfs=no
    rekey=no
    keyingtries=3
    type=transport
    left=%defaultroute
    leftprotoport=udp/l2tp
    leftid=@vpn.l2tp
    right=8.8.9.9 # internet ip
    rightid=10.0.1.2 #
    rightprotoport=udp/l2tp
    auto=add

/etc/ipsec.d/xxx.secrets

@vpn.l2tp %any : PSK "******"

/etc/xl2tpd/xl2tpd.conf

sudo apt-get install strongswan xl2tpd ppp

/etc/ipsec.conf

conn L2TP-PSK

type=transport

authby=psk

keyexchange=ikev1

keyingtries=3

rekey=no

left=192.168.5.105 use local ip

right=%any

auto=add

/etc/ipsec.secrets

: PSK "12345678"

/etc/xl2tpd/xl2tpd.conf

[lns default] ; Our fallthrough LNS definition

ip range = 192.168.2.2-192.168.2.20 ; * Allocate from this IP range

local ip = 192.168.2.1 ; * Our local IP to use