# uname -a
Linux ubuntu 2.6.24-19-server #1 SMP Wed Aug 20 23:54:28 UTC 2008 i686 GNU/Linux

# aptitude install openswan xl2tpd
# dpkg --list openswan xl2tpd
||/ Name           Version        Description
+++-==============-==============-============================================
ii  openswan       1:2.4.9+dfsg-1 IPSEC utilities for Openswan
ii  xl2tpd         1.1.12.dfsg.1- a layer 2 tunneling protocol implementation

# cp /etc/ipsec.d/examples/no_oe.conf /etc/ipsec.d/
# cp /etc/ipsec.d/examples/l2tp-psk.conf /etc/ipsec.d/

# /etc/ipsec.conf - Openswan IPsec configuration file
# RCSID $Id: ipsec.conf.in,v 1.15.2.6 2006/10/19 03:49:46 paul Exp $
# This file:  /usr/share/doc/openswan/ipsec.conf-sample
#
# Manual:     ipsec.conf.5
version	2.0	# conforms to second version of ipsec.conf specification
# basic configuration
config setup
# plutodebug / klipsdebug = "all", "none" or a combation from below:
# "raw crypt parsing emitting control klips pfkey natt x509 private"
# eg: plutodebug="control parsing"
#
# ONLY enable plutodebug=all or klipsdebug=all if you are a developer !!
#
# NAT-TRAVERSAL support, see README.NAT-Traversal
nat_traversal=yes
# virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12
#
# enable this if you see "failed to find any available worker"
nhelpers=0
# Add connections here
# sample VPN connections, see /etc/ipsec.d/examples/
#Disable Opportunistic Encryption
include /etc/ipsec.d/*.conf

conn L2TP-PSK-NAT
rightsubnet=vhost:%priv
left=192.168.144.10
leftnexthop=192.168.144.1
also=L2TP-PSK-noNAT
conn L2TP-PSK-noNAT
#
# Configuration for one user with any type of IPsec/L2TP client
# including the updated Windows 2000/XP (MS KB Q818043), but
# excluding the non-updated Windows 2000/XP.
#
#
# Use a Preshared Key. Disable Perfect Forward Secrecy.
#
# PreSharedSecret needs to be specified in /etc/ipsec.secrets as
# YourIPAddress  %any: "sharedsecret"
authby=secret
pfs=no
auto=add
keyingtries=3
# we cannot rekey for %any, let client rekey
rekey=no
type=transport
#
#left=%defaultroute
# or you can use: left=YourIPAddress
#
# For updated Windows 2000/XP clients,
# to support old clients as well, use leftprotoport=17/%any
leftprotoport=17/1701
#
# The remote user.
#
right=%any
rightprotoport=17/0

# RCSID $Id: ipsec.secrets.proto,v 1.3.6.1 2005/09/28 13:59:14 paul Exp $
# This file holds shared secrets or RSA private keys for inter-Pluto
# authentication.  See ipsec_pluto(8) manpage, and HTML documentation.
# RSA private key for this host, authenticating it to any other host
# which knows the public part.  Suitable public keys, for ipsec.conf, DNS,
# or configuration of other implementations, can be extracted conveniently
# with "ipsec showhostkey".
192.168.144.10 %any: PSK "sharedsecret"

;
; Sample l2tpd configuration file
;
; This example file should give you some idea of how the options for l2tpd
; should work.  The best place to look for a list of all options is in
; the source code itself, until I have the time to write better documetation :)
; Specifically, the file "file.c" contains a list of commands at the end.
;
; You most definitely don't have to spell out everything as it is done here
;
; [global]								; Global parameters:
; port = 1701						 	; * Bind to port 1701
; auth file = /etc/l2tpd/l2tp-secrets 	; * Where our challenge secrets are
; access control = yes					; * Refuse connections without IP match
; rand source = dev                     ; Source for entropy for random
;                                       ; numbers, options are:
;                                       ; dev - reads of /dev/urandom
;                                       ; sys - uses rand()
;                                       ; egd - reads from egd socket
;                                       ; egd is not yet implemented
;
[lns default]							; Our fallthrough LNS definition
; exclusive = no						; * Only permit one tunnel per host
ip range = 192.168.144.128-192.168.144.135	; * Allocate from this IP range
; no ip range = 192.168.0.3-192.168.0.9 ; * Except these hosts
; ip range = 192.168.0.5				; * But this one is okay
; ip range = lac1-lac2					; * And anything from lac1 to lac2's IP
; lac = 192.168.1.4 - 192.168.1.8		; * These can connect as LAC's
; no lac = untrusted.marko.net			; * This guy can't connect
; hidden bit = no						; * Use hidden AVP's?
local ip = 192.168.144.10				; * Our local IP to use
; length bit = yes						; * Use length bit in payload?
; require chap = yes					; * Require CHAP auth. by peer
; refuse pap = yes						; * Refuse PAP authentication
; refuse chap = no						; * Refuse CHAP authentication
; refuse authentication = no			; * Refuse authentication altogether
require authentication = no			; * Require peer to authenticate
; unix authentication = no				; * Use /etc/passwd for auth.
name = myhostname						; * Report this as our hostname
; ppp debug = no						; * Turn on PPP debugging
; pppoptfile = /etc/ppp/options.l2tpd.lns	; * ppp options file
; call rws = 10							; * RWS for call (-1 is valid)
; tunnel rws = 4						; * RWS for tunnel (must be > 0)
; flow bit = yes						; * Include sequence numbers
; challenge = yes						; * Challenge authenticate peer ;
;

# Dump all the variables to the debug log to ensure that the configuration was picked up properly.
#dump
# Output debugging information to /var/log/debug
#debug
# Do not support BSD compression.
nobsdcomp
passive
lock
# Allow all usernames to connect.
name *
proxyarp
ipcp-accept-local
ipcp-accept-remote
lcp-echo-failure 3
lcp-echo-interval 5
nodeflate
# Do not authenticate incoming connections. This is handled by IPsec.
noauth
refuse-chap
refuse-mschap
refuse-mschap-v2
# Set the DNS servers the PPP clients will use.
ms-dns 192.168.144.10
mtu 1450
mru 1450

# /etc/init.d/ipsec restart
# /etc/init.d/xl2tpd restart

ubuntu pluto[11596]: "L2TP-PSK-NAT"[3] 126.248.31.20 #6: STATE_QUICK_R2: IPsec SA established {ESP=>0x08ff0d97 <0xe60b50ab xfrm=AES_128-HMAC_SHA1 NATD=126.248.31.20:4500 DPD=none}

ubuntu xl2tpd[11723]: Call established with 126.248.31.20, Local: 65226, Remote: 210, Serial: 1