openVPN sur debian openVZ

Support Debian
#21

oui

si je regarde le ifconfig de ma vm le serveur est monté

/etc/openvpn# ifconfig
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

tun0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          inet addr:10.66.0.1  P-t-P:10.66.0.2  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

venet0    Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          inet addr:127.0.0.2  P-t-P:127.0.0.2  Bcast:0.0.0.0  Mask:255.255.255.255
          UP BROADCAST POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1
          RX packets:2168 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1927 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:231844 (226.4 KiB)  TX bytes:260748 (254.6 KiB)

venet0:0  Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          inet addr:172.16.0.101  P-t-P:172.16.0.101  Bcast:172.16.0.101  Mask:255.255.255.255
          UP BROADCAST POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1

sur le serveur VPN

/etc/openvpn# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN 
    link/void 
    inet 127.0.0.2/32 scope host venet0
    inet 172.16.0.101/32 brd 172.16.0.101 scope global venet0:0
4: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 100
    link/none 
    inet 10.66.0.1 peer 10.66.0.2/32 scope global tun0
/etc/openvpn# ip route
10.66.0.2 dev tun0  proto kernel  scope link  src 10.66.0.1 
10.66.0.0/24 via 10.66.0.2 dev tun0 
10.2.0.0/24 via 10.66.0.2 dev tun0 
10.1.0.0/24 via 10.66.0.2 dev tun0 
default dev venet0  scope link

sur le client qui est à l’autre bout du vpn

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether fc:75:16:61:3c:9d brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.254/24 brd 192.168.1.255 scope global eth2
    inet6 fe80::fe75:16ff:fe61:3c9d/64 scope link 
       valid_lft forever preferred_lft forever
3: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether 00:10:18:2c:1e:00 brd ff:ff:ff:ff:ff:ff
    inet 10.1.0.254/24 brd 10.1.0.255 scope global eth0
    inet6 fe80::210:18ff:fe2c:1e00/64 scope link 
       valid_lft forever preferred_lft forever
4: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:13:72:37:d4:01 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.254/24 brd 192.168.0.255 scope global eth1
    inet6 fe80::213:72ff:fe37:d401/64 scope link 
       valid_lft forever preferred_lft forever
5: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN 
    link/void 
193.252.22.91 via 192.168.1.1 dev eth2 
10.1.0.253 dev venet0  scope link 
192.168.1.0/24 dev eth2  proto kernel  scope link  src 192.168.1.254 
192.168.0.0/24 dev eth1  proto kernel  scope link  src 192.168.0.254 
10.1.0.0/24 dev eth0  proto kernel  scope link  src 10.1.0.254 
default via 192.168.0.1 dev eth1
#22

Apparemment le client n’est pas connecté au VPN car je ne vois pas d’interface tun.
Peux-tu en dire plus sur ce client et sur ses nombreuses interfaces ? Quel est le chemin réseau pour atteindre le serveur VPN ? A quelle adresse de serveur essaie-t-il de se connecter ?

Côté serveur, y a-t-il une redirection du port OpenVPN de l’hôte vers la VM ? La VM a-t-elle une connectivité avec l’extérieur ?

Peux-tu préciser ce que tu écrivais précédemment :

[quote=“Minus”]sur le firewall le port 1194 est bien ouvert
bref le serveur à l’autre bout du vpn ne repond toujours pas aux ping[/quote]

#23

alors:

il y a effectivement une redirection de port mais uniquement pour la connexion ssh.

Aprés mon FAI, au niveau du routeur fibre redirige comme suis: 1194 (UDP) -> 172.16.0.101 (donc l’ip de la vm openvpn)

le client:

eth1 c’est l’adsl
eth2 c’est la fibre
eth0 c’est la lan

le tun0 du client devrait etre configuré comme cela:
tun0: inet adr:10.66.0.78 P-t-P:10.66.0.77 Masque:255.255.255.255

Côté serveur, y a-t-il une redirection du port OpenVPN de l’hôte vers la VM ? non

voila l’iptable de l’hote

 iptables-save
# Generated by iptables-save v1.4.14 on Tue Aug 11 13:58:48 2015
*nat
:PREROUTING ACCEPT [187097]
:POSTROUTING ACCEPT [131519:8071337]
:OUTPUT ACCEPT [60885:4038781]
COMMIT
# Completed on Tue Aug 11 13:58:48 2015
# Generated by iptables-save v1.4.14 on Tue Aug 11 13:58:48 2015
*mangle
:PREROUTING ACCEPT [4720471:2748290796]
:INPUT ACCEPT [1678234:2312664393]
:FORWARD ACCEPT [3046427:436433914]
:OUTPUT ACCEPT [1284243:125554181]
:POSTROUTING ACCEPT [4330674:562021130]
COMMIT
# Completed on Tue Aug 11 13:58:48 2015
# Generated by iptables-save v1.4.14 on Tue Aug 11 13:58:48 2015
*filter
:INPUT ACCEPT [1678234:2312664393]
:FORWARD ACCEPT [3046427:436433914]
:OUTPUT ACCEPT [1282833:125425207]
COMMIT
# Completed on Tue Aug 11 13:58:48 2015

La vm a une connectivité vers l’exterieur puisque je peux ping et dl en direct a partir d’elle.

Le port 1194 est bien ouvert au niveau du firewall ici en local, donc pas de blocage de ce coté la.

voila

merci pour ton aide

#24

Depuis quelle machine vers quelle adresse ? Le routeur vers la VM ?

Au pire, lance une capture de trafic avec [mono]tcpdump[/mono], [mono]wireshark[/mono] ou équivalent sur chaque interface censée voir passer les paquets du VPN en UDP 1194 pendant une tentative de connexion du client openvpn pour voir où les paquets sont bloqués. Sur le client, sur l’hôte et sur la VM.

#25

la redirection du port xxx ssh c’est pour la connexion au serveur de l’autre coté du VPN, ou ce port est bien indiqué dans le sshd-config. Donc juste un changement de port pour la connexion ssh.

J’ai ici une regle de redirection ssh dans le routeur FAI de ce même port vers la vm 172.16.0.101, mais sans que ce port soit indiqué dans le sshd_config. Donc juste un changement de port pour la connexion ssh.

alors j’ai lancé tcpdump -ni any port 1194sur la VM, aucun retour, sur le serveur derriere le vpn, aucun retour.

Sur le client j’ai regardé le fichier client.conf et trouvé dedans:

[code]# The hostname/IP and port of the server.

You can have multiple remote entries

to load balance between the servers.

; fibre
remote siege.maboite.com 1194[/code]

hors

siege.maboite.com est tombé en même temps que le serveur jeudi…

donc j’ai modifié dans le client.conf la ligne comme suis “remote ippublique 1194” et la par miracle le vpn c’est monté et fonctionne.

Perso j’aurais directement mis l’ip, quelle idée de confier ça a un serveur dns !!!

Bon maintenant me reste une derniere chose à régler ce sont les nomades:

avec la modif ci dessus pas de soucis, par contre ils entrent login et mdp et sont jetés:

Tue Aug 11 15:33:22 2015 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication
Tue Aug 11 15:33:22 2015 Data Channel Decrypt: Cipher 'BF-CBC' initialized with 128 bit key
Tue Aug 11 15:33:22 2015 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication
Tue Aug 11 15:33:22 2015 Control Channel: TLSv1, cipher TLSv1/SSLv3 DHE-RSA-AES256-SHA, 1024 bit RSA
Tue Aug 11 15:33:22 2015 [vpn] Peer Connection Initiated with [AF_INET]xxx.xxx.xxx.xxx:1194
Tue Aug 11 15:33:23 2015 MANAGEMENT: >STATE:1439300003,GET_CONFIG,,,
Tue Aug 11 15:33:24 2015 SENT CONTROL [vpn]: 'PUSH_REQUEST' (status=1)
Tue Aug 11 15:33:24 2015 AUTH: Received control message: AUTH_FAILED
Tue Aug 11 15:33:24 2015 SIGUSR1[soft,auth-failure] received, process restarting
Tue Aug 11 15:33:24 2015 MANAGEMENT: >STATE:1439300004,RECONNECTING,auth-failure,,
Tue Aug 11 15:33:24 2015 Restart pause, 2 second(s)
Tue Aug 11 15:33:24 2015 MANAGEMENT: CMD 'auth-retry none'
Tue Aug 11 15:33:26 2015 Socket Buffers: R=[8192->8192] S=[8192->8192]
Tue Aug 11 15:33:26 2015 MANAGEMENT: >STATE:1439300006,RESOLVE,,,
Tue Aug 11 15:33:26 2015 UDPv4 link local: [undef]
Tue Aug 11 15:33:26 2015 UDPv4 link remote: [AF_INET]xxx.xxx.xxx.xxx:1194
Tue Aug 11 15:33:26 2015 MANAGEMENT: >STATE:1439300006,WAIT,,,
Tue Aug 11 15:33:26 2015 MANAGEMENT: >STATE:1439300006,AUTH,,,
Tue Aug 11 15:33:26 2015 TLS: Initial packet from [AF_INET]xxx.xxx.xxx.xxx:1194, sid=5c375577 797d55f5
Tue Aug 11 15:33:35 2015 MANAGEMENT: Client disconnected
Tue Aug 11 15:33:35 2015 ERROR: could not read Auth username/password/ok/string from management interface
Tue Aug 11 15:33:35 2015 Exiting due to fatal error

est ce que c’est le fait que ce serveur n’est pas dans le domaine ou ce n’est pas en rapport avec ça et c’est autre chose?

En tout cas merci beaucoup pour ton aide et surtout ta patience :wink:

#26

Ce n’est pas faute de t’avoir demandé à quelle adresse le client essayait de se connecter quelques messages plus haut…

Je ne vois pas le rapport. L’adresse IP avait forcément changé, donc soit tu pouvais modifier par DNS l’adresse IP associée au nom de domaine “siege.maboite.com” inscrit dans la conf client, soit tu devais modifier le nom de domaine ou l’adresse IP dans la conf client. Le DNS c’est bien, ça ajoute de la souplesse.

Je n’en sais rien. Comme déjà dit, je n’ai jamais utilisé openvpn. Je croyais que ça utilisait une authentification par certificat/clés. De quel domaine parles-tu ? D’où viennent ces logins et mots de passe ? Toi, comment t’es-tu authentifié ?

#27

Bon je me suis rejouis un peu trop vite quand même il y a encore des bugs

Pour modifier le client.conf sur le serveur distant je me suis connecté via teamviewer sur un PC distant

Par contre, j’essaye maintenant de me connecter en ssh sur le serveur distant via l’ip 10.1.0.254 (comme je le faisait avant avec le port ssh modifié), donc la pate lan du serveur distant, et impossible connexion refusée.

De même si je cherche à me connecter en ssh sur les Pc lan distants.

Pour la connexion vpn nomade:

Perso je ne peux pas m’authentifier en étant dans la lan, j’ai donc contacté un user nomade, modifié son client.conf, il s’est connecté et une fenêtre est apparu avec demande de login et mdp.
il a entré les mêmes login et mdp que avant et pas de connexion possible.

#28

Salut,

Il est tout à fait possible que ce soit un soucis avec le routage.
Pour s’en assurer, il est indispensable que tu nous copie/colle les fichiers de configuration de OpenVPN pour “client” et pour “serveur”. Tu peux y censurer les adresses IP publiques, si tu préfères.

Avec OpenVPN, un serveur peut contenir des directives dans son fichier de configuration pour pousser des routes vers le client. CAD pour demander au client d’ajouter telle ou telle route.
Or, si tu as du reprendre la configuration de “serveur”, il te manque peut-être alors ces directives.

N’hésites pas à ajouter la table de routage coté “serveur” et “client” lorsque le VPN est établi, avec la commande [mono]ip route[/mono] .

–
AnonymousCoward

#29

Merci

je te met ça demain matin sans faute

Pour la conf oui, j’ai repris la conf deja existante que j’avais sauvegardé dans un coin et j’ai l’ai collé dans la nouvelle vm.

Je voulais surtout éviter d’avoir a régénérer les certificats et clés déjà existants.

#30

Bonjour

alors voila les infos:

Coté client:

le fichier client.conf:

##############################################

# Sample client-side OpenVPN 2.0 config file #
# for connecting to multi-client server. #
#                                            #
# This configuration can be used by multiple #
# clients, however each client should have #
# its own cert and key files.                #
#                                            #
# On Windows, you might want to rename this #
# file so it has a .ovpn extension           #
############################################## 

# Specify that we are a client and that we
# will be pulling certain config file directives
# from the server.
client

# Use the same setting as you are using on
# the server.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun

# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel
# if you have more than one. On XP SP2,
# you may need to disable the firewall
# for the TAP adapter.
;dev-node MyTap 

# Are we connecting to a TCP or
# UDP server? Use the same setting as
# on the server.
;proto tcp
proto udp 

# The hostname/IP and port of the server.
# You can have multiple remote entries
# to load balance between the servers.
; fibre
remote ippublique_fibre 1194
; orange
;remote ippublique_adsl 1194
;remote my-server-2 1194 

# Choose a random host from the remote
# list for load-balancing. Otherwise
# try hosts in the order specified.
;remote-random

# Keep trying indefinitely to resolve the
# host name of the OpenVPN server. Very useful
# on machines which are not permanently connected
# to the internet such as laptops.
resolv-retry infinite

# Most clients don't need to bind to
# a specific local port number.
nobind

# Downgrade privileges after initialization (non-Windows only)
;user nobody
;group nogroup

# Try to preserve some state across restarts.
persist-key
persist-tun

# If you are connecting through an
# HTTP proxy to reach the actual OpenVPN
# server, put the proxy server/IP and
# port number here. See the man page
# if your proxy server requires
# authentication.
;http-proxy-retry # retry on connection failures
;http-proxy [proxy server] [proxy port #]

# Wireless networks often produce a lot
# of duplicate packets. Set this flag
# to silence duplicate packet warnings.
;mute-replay-warnings

# OpenVPN doit utiliser une authentification PAM
auth-user-pass client.pwd

# SSL/TLS parms.
# See the server config file for more
# description. It's best to use
# a separate .crt/.key file pair
# for each client. A single ca
# file can be used for all clients.
ca ca.crt
cert serveurclient.crt
key serveurclient.key

# Verify server certificate by checking
# that the certicate has the nsCertType
# field set to "server". This is an
# important precaution to protect against
# a potential attack discussed here:
# http://openvpn.net/howto.html#mitm

# To use this feature, you will need to generate
# your server certificates with the nsCertType
# field set to "server". The build-key-server
# script in the easy-rsa folder will do this.
ns-cert-type server 

# If a tls-auth key is used on the server
# then every client must also have the key.
;tls-auth ta.key 1

# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.
cipher BF-CBC
;cipher RC2-40-CBC 

# Enable compression on the VPN link.
# Don't enable this unless it is also
# enabled in the server config file.
comp-lzo 

# Set log file verbosity.
verb 3 

# Silence repeating messages
;mute 20

le resultat de l’ip route a partir du serveur client vpn:

193.252.22.91 via 192.168.1.1 dev eth2 
10.66.0.77 dev tun0  proto kernel  scope link  src 10.66.0.78 
10.1.0.253 dev venet0  scope link 
10.2.0.0/24 via 10.66.0.77 dev tun0 
10.66.0.0/24 via 10.66.0.77 dev tun0 
10.0.0.0/24 via 10.66.0.77 dev tun0 
172.16.0.0/24 via 10.66.0.77 dev tun0 
192.168.1.0/24 dev eth2  proto kernel  scope link  src 192.168.1.254 
192.168.0.0/24 dev eth1  proto kernel  scope link  src 192.168.0.254 
10.1.0.0/24 dev eth0  proto kernel  scope link  src 10.1.0.254 
default via 192.168.0.1 dev eth1

Coté serveur:

le fichier server.conf:

#################################################
# Sample OpenVPN 2.0 config file for            #
# multi-client server.                          #
#                                               #
# This file is for the server side              #
# of a many-clients <-> one-server              #
# OpenVPN configuration.                        #
#                                               #
# OpenVPN also supports                         #
# single-machine <-> single-machine             #
# configurations (See the Examples page         #
# on the web site for more info).               #
#                                               #
# This config should work on Windows            #
# or Linux/BSD systems.  Remember on            #
# Windows to quote pathnames and use            #
# double backslashes, e.g.:                     #
# "C:\\Program Files\\OpenVPN\\config\\foo.key" #
#                                               #
# Comments are preceded with '#' or ';'         #
#################################################

# Which local IP address should OpenVPN
# listen on? (optional)
;local a.b.c.d

# Which TCP/UDP port should OpenVPN listen on?
# If you want to run multiple OpenVPN instances
# on the same machine, use a different port
# number for each one.  You will need to
# open up this port on your firewall.
port 1194

# TCP or UDP server?
;proto tcp
proto udp

# "dev tun" will create a routed IP tunnel,
# "dev tap" will create an ethernet tunnel.
# Use "dev tap0" if you are ethernet bridging
# and have precreated a tap0 virtual interface
# and bridged it with your ethernet interface.
# If you want to control access policies
# over the VPN, you must create firewall
# rules for the the TUN/TAP interface.
# On non-Windows systems, you can give
# an explicit unit number, such as tun0.
# On Windows, use "dev-node" for this.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun

# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel if you
# have more than one.  On XP SP2 or higher,
# you may need to selectively disable the
# Windows firewall for the TAP adapter.
# Non-Windows systems usually don't need this.
;dev-node MyTap

# SSL/TLS root certificate (ca), certificate
# (cert), and private key (key).  Each client
# and the server must have their own cert and
# key file.  The server and all clients will
# use the same ca file.
#
# See the "easy-rsa" directory for a series
# of scripts for generating RSA certificates
# and private keys.  Remember to use
# a unique Common Name for the server
# and each of the client certificates.
#
# Any X509 key management system can be used.
# OpenVPN can also use a PKCS #12 formatted key file
# (see "pkcs12" directive in man page).
ca ca.crt
cert vpn.crt
key vpn.key  # This file should be kept secret

# Diffie hellman parameters.
# Generate your own with:
#   openssl dhparam -out dh1024.pem 1024
# Substitute 2048 for 1024 if you are using
# 2048 bit keys. 
dh dh1024.pem

# Configure server mode and supply a VPN subnet
# for OpenVPN to draw client addresses from.
# The server will take 10.0.0.1 for itself,
# the rest will be made available to clients.
# Each client will be able to reach the server
# on 10.0.0.1. Comment this line out if you are
# ethernet bridging. See the man page for more info.
server 10.66.0.0 255.255.255.0

# Maintain a record of client <-> virtual IP address
# associations in this file.  If OpenVPN goes down or
# is restarted, reconnecting clients can be assigned
# the same virtual IP address from the pool that was
# previously assigned.
ifconfig-pool-persist ipp.txt

# Configure server mode for ethernet bridging.
# You must first use your OS's bridging capability
# to bridge the TAP interface with the ethernet
# NIC interface.  Then you must manually set the
# IP/netmask on the bridge interface, here we
# assume 10.0.0.4/255.255.255.0.  Finally we
# must set aside an IP range in this subnet
# (start=10.0.0.50 end=10.0.0.100) to allocate
# to connecting clients.  Leave this line commented
# out unless you are ethernet bridging.
;server-bridge 10.0.0.4 255.255.255.0 10.0.0.50 10.0.0.100

# Configure server mode for ethernet bridging
# using a DHCP-proxy, where clients talk
# to the OpenVPN server-side DHCP server
# to receive their IP address allocation
# and DNS server addresses.  You must first use
# your OS's bridging capability to bridge the TAP
# interface with the ethernet NIC interface.
# Note: this mode only works on clients (such as
# Windows), where the client-side TAP adapter is
# bound to a DHCP client.
;server-bridge

# Push routes to the client to allow it
# to reach other private subnets behind
# the server.  Remember that these
# private subnets will also need
# to know to route the OpenVPN client
# address pool (10.0.0.0/255.255.255.0)
# back to the OpenVPN server.
;push "route 192.168.10.0 255.255.255.0"
;push "route 192.168.20.0 255.255.255.0"
push "route 172.16.0.0 255.255.255.0"
push "route 10.0.0.0 255.255.255.0"
push "dhcp-option DNS 172.16.0.1"
push "dhcp-option WINS 172.16.0.114"

# To assign specific IP addresses to specific
# clients or if a connecting client has a private
# subnet behind it that should also have VPN access,
# use the subdirectory "ccd" for client-specific
# configuration files (see man page for more info).

# EXAMPLE: Suppose the client
# having the certificate common name "Thelonious"
# also has a small subnet behind his connecting
# machine, such as 192.168.40.128/255.255.255.248.
# First, uncomment out these lines:
;client-config-dir ccd
;route 192.168.40.128 255.255.255.248
client-config-dir ccd
# route controls the routing from the kernel to the OpenVPN server (via the TUN 
interface)
# iroute controls the routing from the OpenVPN server to the remote clients. Bot
h are necessary
route 10.1.0.0 255.255.255.0
route 10.2.0.0 255.255.255.0
# Then create a file ccd/Thelonious with this line:
#   iroute 192.168.40.128 255.255.255.248
# This will allow Thelonious' private subnet to
# access the VPN.  This example will only work
# if you are routing, not bridging, i.e. you are
# using "dev tun" and "server" directives.

# EXAMPLE: Suppose you want to give
# Thelonious a fixed VPN IP address of 10.9.0.1.
# First uncomment out these lines:
;client-config-dir ccd
;route 10.9.0.0 255.255.255.252
# Then add this line to ccd/Thelonious:
#   ifconfig-push 10.9.0.1 10.9.0.2

# Suppose that you want to enable different
# firewall access policies for different groups
# of clients.  There are two methods:
# (1) Run multiple OpenVPN daemons, one for each
#     group, and firewall the TUN/TAP interface
#     for each group/daemon appropriately.
# (2) (Advanced) Create a script to dynamically
#     modify the firewall in response to access
#     from different clients.  See man
#     page for more info on learn-address script.
;learn-address ./script

# If enabled, this directive will configure
# all clients to redirect their default
# network gateway through the VPN, causing
# all IP traffic such as web browsing and
# and DNS lookups to go through the VPN
# (The OpenVPN server machine may need to NAT
# or bridge the TUN/TAP interface to the internet
# in order for this to work properly).
;push "redirect-gateway def1 bypass-dhcp"

# Certain Windows-specific network settings
# can be pushed to clients, such as DNS
# or WINS server addresses.  CAVEAT:
# http://openvpn.net/faq.html#dhcpcaveats
# The addresses below refer to the public
# DNS servers provided by opendns.com.
;push "dhcp-option DNS 208.67.222.222"
;push "dhcp-option DNS 208.67.220.220"

# Uncomment this directive to allow different
# clients to be able to "see" each other.
# By default, clients will only see the server.
# To force clients to only see the server, you
# will also need to appropriately firewall the
# server's TUN/TAP interface.
client-to-client

# Uncomment this directive if multiple clients
# might connect with the same certificate/key
# files or common names.  This is recommended
# only for testing purposes.  For production use,
# each client should have its own certificate/key
# pair.
#
# IF YOU HAVE NOT GENERATED INDIVIDUAL
# CERTIFICATE/KEY PAIRS FOR EACH CLIENT,
# EACH HAVING ITS OWN UNIQUE "COMMON NAME",
# UNCOMMENT THIS LINE OUT.
;duplicate-cn

# The keepalive directive causes ping-like
# messages to be sent back and forth over
# the link so that each side knows when
# the other side has gone down.
# Ping every 10 seconds, assume that remote
# peer is down if no ping received during
# a 120 second time period.
keepalive 10 120

# For extra security beyond that provided
# by SSL/TLS, create an "HMAC firewall"
# to help block DoS attacks and UDP port flooding.
#
# Generate with:
#   openvpn --genkey --secret ta.key
#
# The server and each client must have
# a copy of this key.
# The second parameter should be '0'
# on the server and '1' on the clients.
;tls-auth ta.key 0 # This file is secret

# Select a cryptographic cipher.
# This config item must be copied to
# the client config file as well.
;cipher BF-CBC        # Blowfish (default)
;cipher AES-128-CBC   # AES
;cipher DES-EDE3-CBC  # Triple-DES
cipher BF-CBC
;cipher RC2-40-CBC

# Enable compression on the VPN link.
# If you enable it here, you must also
# enable it in the client config file.
comp-lzo

# The maximum number of concurrently connected
# clients we want to allow.
;max-clients 100

# It's a good idea to reduce the OpenVPN
# daemon's privileges after initialization.
#
# You can uncomment this out on
# non-Windows systems.
user nobody
group nogroup

# l'obligation d'utiliser pam pour l'authentification
plugin /usr/lib/openvpn/openvpn-auth-pam.so common-auth

# The persist options will try to avoid
# accessing certain resources on restart
# that may no longer be accessible because
# of the privilege downgrade.
persist-key
persist-tun

# Output a short status file showing
# current connections, truncated
# and rewritten every minute.
status openvpn-status.log

# By default, log messages will go to the syslog (or
# on Windows, if running as a service, they will go to
# the "\Program Files\OpenVPN\log" directory).
# Use log or log-append to override this default.
# "log" will truncate the log file on OpenVPN startup,
# while "log-append" will append to it.  Use one
# or the other (but not both).
;log         openvpn.log
log-append  /var/log/openvpn.log

# Set the appropriate level of log
# file verbosity.
#
# 0 is silent, except for fatal errors
# 4 is reasonable for general usage
# 5 and 6 can help to debug connection problems
# 9 is extremely verbose
verb 3

# Silence repeating messages.  At most 20
# sequential messages of the same message
# category will be output to the log.
;mute 20

# for smb perf
;link-mtu 1456
;mssfix 1412

# Revoked certificate list
crl-verify /etc/openvpn/crl.pem

et voila l’ip route à partir du serveur VPN

ip route
10.66.0.2 dev tun0  proto kernel  scope link  src 10.66.0.1 
10.66.0.0/24 via 10.66.0.2 dev tun0 
10.2.0.0/24 via 10.66.0.2 dev tun0 
10.1.0.0/24 via 10.66.0.2 dev tun0 
default dev venet0  scope link

par avance merci pour ton aide