apt-get update
apt-get install strongswan xl2tpd net-tools

# ipsec.conf - strongSwan IPsec configuration file

conn myvpn
  auto=route
  keyexchange=ikev1
  authby=secret
  type=transport
  left=%defaultroute
  leftprotoport=17/1701
  rightprotoport=17/1701
  right=<server_address>
  ike=aes128-sha1-modp2048
  esp=aes128-sha1

: PSK "ipsec_password"

[lac l2tp_client]
lns = <server_address>
autodial = yes
redial = yes
redial timeout = 10
ppp debug = yes
pppoptfile = /etc/ppp/options.l2tpd.client
length bit = yes
/etc/ppp/options.l2tpd.client:

ipcp-accept-local
ipcp-accept-remote
refuse-eap
require-chap
noccp
noauth
mtu 1280
mru 1280
noipdefault
defaultroute
usepeerdns
connect-delay 5000
name "l2tp_username"
password "l2tp_password"

service strongswan start
service xl2tpd start