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[[Category:Virtual Private Network]]
[[de:OpenVPN]]
[[zh-CN:OpenVPN]]
[[en:OpenVPN]]
{{Expansion|(at least) add support for IPv6 and L2 Ethernet bridging}}
Эта статья описывает базовую установку и настройку [http://openvpn.net OpenVPN], чего достаточно для частного использования или малой офисной сети. Больше информации можно найти на странице [https://community.openvpn.net/openvpn/wiki/Openvpn23ManPage OpenVPN 2.3 man page] и на странице [http://openvpn.net/index.php/open-source/documentation OpenVPN документации].
OpenVPN мощный и гибкий [[Wikipedia:VPN|VPN]] демон. OpenVPN поддерживает [[Wikipedia:SSL/TLS|SSL/TLS]] безопасность, [[Wikipedia:Bridging_(networking)|Ethernet bridging]], [[Wikipedia:Transmission_Control_Protocol|TCP]] или [[Wikipedia:User_Datagram_Protocol|UDP]] [[Wikipedia:Tunneling_protocol|tunnel transport]] through [[Wikipedia:Proxy_server|proxies]] or [[Wikipedia:Network address translation|NAT]], поддерживает [[Wikipedia:Dynamic_Host_Configuration_Protocol|DHCP]], масштабируется на сотни и тысячи пользователей, и портируемость между большинством ОС.
OpenVPN is tightly bound to the [http://www.openssl.org OpenSSL] library, and derives much of its crypto capabilities from it.
OpenVPN supports conventional encryption using a [[Wikipedia:Pre-shared_key|pre-shared secret key]] (Static Key mode) or [[Wikipedia:Public_key|public key security]] ([[Wikipedia:SSL/TLS|SSL/TLS]] mode) using client & server certificates. OpenVPN also supports unencrypted TCP/UDP tunnels.
OpenVPN разработана для использования с [[Wikipedia:TUN/TAP|TUN/TAP]] виртуальными сетевыми интерфейсами, имеющимися на множестве платформ.
Overall, OpenVPN aims to offer many of the key features of [[Wikipedia:Ipsec|IPSec]] but with a relatively lightweight footprint.
OpenVPN была написана James Yonan и распространяется под лицензией [[Wikipedia:GNU General Public License|GNU General Public License (GPL)]].
== Установка OpenVPN ==
[[pacman|Install]] {{Pkg|openvpn}} from the [[official repositories]].
{{Примечание|OpenVPN поддерживает из The software contained in this package supports both server and client mode, so install it on all machines that need to create VPN connections.}}
== Configure the system for TUN/TAP support ==
OpenVPN требует поддержки TUN/TAP. Удостоверьтесь в загрузке {{ic|tun}} модуля.
Прочтите [[Kernel modules]].
По умолчанию ядро уже настроено, но если Вы используете другое ядро, тогда проверьте что модуль TUN/TAP загружен. Если {{ic|$ zgrep CONFIG_TUN /proc/config.gz}} возвратит {{ic|1=CONFIG_TUN=n}}, тогда перенастройте конфигурационный файл ядра и пересоберите ядро.
{{hc|Kernel config file|
Device Drivers
--> Network device support
[M] Universal TUN/TAP device driver support}}
== Connect to a VPN provided by a third party ==
To connect to a VPN provided by a third party, most of the following can most likely be ignored. Use the certificates and instructions given by your provider, for instance see: [[Airvpn]].
{{Note|To connect to servers of the most VPN providers that offer free service, one can plainly use [[pptpd]] since most offers only this protocol.}}
== Create a Public Key Infrastructure (PKI) from scratch ==
If you are setting up OpenVPN from scratch, you will need to create a [[Wikipedia:Public key infrastructure|Public Key Infrastructure (PKI)]].
Create the needed certificates and keys by following: [[Create a Public Key Infrastructure Using the easy-rsa Scripts]].
The final step of the key creation process is to copy the files needed to the correct machines through a secure channel.
{{Note|The rest of this article assumes that the keys and certificates are placed in {{ic|/etc/openvpn}}.}}
The public ca.crt certificate is needed on all servers and clients. The private ca.key key is secret and only needed on the key generating machine.
A server needs server.crt, dh2048.pem (public), server.key, and ta.key (private).
A client needs client.crt (public), client.key, and ta.key (private).
== A basic L3 IP routing configuration ==
{{Note|Unless otherwise explicitly stated, the rest of this article assumes this basic configuration.}}
OpenVPN is an extremely versatile piece of software and many configurations are possible, in fact machines can be both "servers" and "clients", blurring the distinction between server and client.
What really distinguishes a server from a client (apart from the type of certificate used) is the configuration file itself. The OpenVPN daemon start-up script reads all the .conf configuration files it finds in {{ic|/etc/openvpn}} on start-up and acts accordingly. If it finds more than one configuration file, it will start one OpenVPN process per configuration file.
This article explains how to set up a server named elmer and a client that connects to it named bugs. More servers and clients can easily be added by creating more key/certificate pairs and adding more server and client configuration files.
The OpenVPN package comes with a collection of example configuration files for different purposes. The sample server and client configuration files make an ideal starting point for a basic OpenVPN setup with the following features:
* Uses [[Wikipedia:Public key infrastructure|Public Key Infrastructure (PKI)]] for authentication.
* Creates a VPN using a virtual TUN network interface (OSI L3 IP routing).
* Listens for client connections on UDP port 1194 (OpenVPN's [[Wikipedia:Port_number|official IANA port number]]).
* Distributes virtual addresses to connecting clients from the 10.8.0.0/24 subnet.
For more advanced configurations, please see the official [http://openvpn.net/index.php/manuals/427-openvpn-22.html OpenVPN 2.2 man page] and the [http://openvpn.net/index.php/open-source/documentation OpenVPN documentation].
=== The server configuration file ===
Copy the example server configuration file to {{ic|/etc/openvpn/server.conf}}:
# cp /usr/share/openvpn/examples/server.conf /etc/openvpn/server.conf
Edit the following:
* The {{ic|ca}}, {{ic|cert}}, {{ic|key}}, and {{ic|dh}} parameters to reflect the path and names of the keys and certificates. Specifying the paths will allow you to run the OpenVPN executable from any directory for testing purposes.
* Enable the SSL/TLS HMAC handshake protection. '''Note the use of the parameter 0 for a server'''.
* It is recommended to run OpenVPN with reduced privileges once it has initialized. Do this by uncommenting the {{ic|user}} and {{ic|group}} directives.
{{hc|/etc/openvpn/server.conf|
ca /etc/openvpn/ca.crt
cert /etc/openvpn/elmer.crt
key /etc/openvpn/elmer.key
dh /etc/openvpn/dh2048.pem
.
.
tls-auth /etc/openvpn/ta.key '''0'''
.
.
user nobody
group nobody
}}
{{Note|Note that if the server is behind a firewall or a NAT translating router, you will have to forward the OpenVPN UDP port (1194) to the server.}}
=== The client configuration file ===
Copy the example client configuration file to {{ic|/etc/openvpn/client.conf}}:
# cp /usr/share/openvpn/examples/client.conf /etc/openvpn/client.conf
Edit the following:
* The {{ic|remote}} directive to reflect either the server's [[Wikipedia:Fully qualified domain name|Fully Qualified Domain Name]], hostname (as known to the client), or its IP address.
* Uncomment the {{ic|user}} and {{ic|group}} directives to drop privileges.
* The {{ic|ca}}, {{ic|cert}}, and {{ic|key}} parameters to reflect the path and names of the keys and certificates.
* Enable the SSL/TLS HMAC handshake protection. '''Note the use of the parameter 1 for a client'''.
{{hc|/etc/openvpn/client.conf|
remote elmer.acmecorp.org 1194
.
.
user nobody
group nobody
.
.
ca /etc/openvpn/ca.crt
cert /etc/openvpn/bugs.crt
key /etc/openvpn/bugs.key
.
.
tls-auth /etc/openvpn/ta.key '''1'''
}}
=== Testing the OpenVPN configuration ===
Run {{ic|# openvpn /etc/openvpn/server.conf}} on the server, and {{ic|# openvpn /etc/openvpn/client.conf}} on the client. You should see something similar to this:
{{hc|# openvpn /etc/openvpn/server.conf|2=
Wed Dec 28 14:41:26 2011 OpenVPN 2.2.1 x86_64-unknown-linux-gnu [SSL] [LZO2] [EPOLL] [eurephia] built on Aug 13 2011
Wed Dec 28 14:41:26 2011 NOTE: OpenVPN 2.1 requires '--script-security 2' or higher to call user-defined scripts or executables
Wed Dec 28 14:41:26 2011 Diffie-Hellman initialized with 2048 bit key
.
.
Wed Dec 28 14:41:54 2011 bugs/95.126.136.73:48904 MULTI: primary virtual IP for bugs/95.126.136.73:48904: 10.8.0.6
Wed Dec 28 14:41:57 2011 bugs/95.126.136.73:48904 PUSH: Received control message: 'PUSH_REQUEST'
Wed Dec 28 14:41:57 2011 bugs/95.126.136.73:48904 SENT CONTROL [bugs]: 'PUSH_REPLY,route 10.8.0.1,topology net30,ping 10,ping-restart 120,ifconfig 10.8.0.6 10.8.0.5' (status=1)
}}
{{hc|# openvpn /etc/openvpn/client.conf|2=
Wed Dec 28 14:41:50 2011 OpenVPN 2.2.1 i686-pc-linux-gnu [SSL] [LZO2] [EPOLL] [eurephia] built on Aug 13 2011
Wed Dec 28 14:41:50 2011 NOTE: OpenVPN 2.1 requires '--script-security 2' or higher to call user-defined scripts or executables
Wed Dec 28 14:41:50 2011 LZO compression initialized
.
.
Wed Dec 28 14:41:57 2011 GID set to nobody
Wed Dec 28 14:41:57 2011 UID set to nobody
Wed Dec 28 14:41:57 2011 Initialization Sequence Completed
}}
On the server, find the IP address assigned to the tunX device:
{{hc|# ip addr show|2=
.
.
40: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 100
link/none
inet 10.8.0.1 peer 10.8.0.2/32 scope global tun0
}}
Here we see that the server end of the tunnel has been given the IP address 10.8.0.1.
Do the same on the client:
{{hc|# ip addr show|2=
.
.
37: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 100
link/none
inet 10.8.0.6 peer 10.8.0.5/32 scope global tun0
}}
And the client side has been given the IP address 10.8.0.6.
Now try pinging the interfaces.
On the server:
{{hc|# ping -c3 10.8.0.6|2=
PING 10.8.0.6 (10.8.0.6) 56(84) bytes of data.
64 bytes from 10.8.0.6: icmp_req=1 ttl=64 time=238 ms
64 bytes from 10.8.0.6: icmp_req=2 ttl=64 time=237 ms
64 bytes from 10.8.0.6: icmp_req=3 ttl=64 time=205 ms
--- 10.8.0.6 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 205.862/227.266/238.788/15.160 ms
}}
On the client:
{{hc|# ping -c3 10.8.0.1|2=
PING 10.8.0.1 (10.8.0.1) 56(84) bytes of data.
64 bytes from 10.8.0.1: icmp_req=1 ttl=64 time=158 ms
64 bytes from 10.8.0.1: icmp_req=2 ttl=64 time=158 ms
64 bytes from 10.8.0.1: icmp_req=3 ttl=64 time=157 ms
--- 10.8.0.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2001ms
rtt min/avg/max/mdev = 157.426/158.278/158.940/0.711 ms
}}
You now have a working OpenVPN installation, and your client (bugs) will be able to use services on the server (elmer), and vice versa.
{{Note|If using a firewall, make sure that IP packets on the TUN device are not blocked.}}
=== Configure the MTU with Fragment and MSS ===
{{Note|If you do not configure MTU, then you will notice that small packets like ping and DNS will work, however web browsing will not work.}}
Now it is time to configure the maximum segment size (MSS). In order to do this we need to discover what is the smallest MTU along the path between the client and server. In order to do this you can ping the server and disable fragmentation. Then specify the max packet size.
{{hc|# ping -c5 -M do -s 1500 elmer.acmecorp.org|2=
PING elmer.acmecorp.org (99.88.77.66) 1500(1528) bytes of data.
From 1.2.3.4 (99.88.77.66) icmp_seq=1 Frag needed and DF set (mtu = 576)
From 1.2.3.4 (99.88.77.66) icmp_seq=1 Frag needed and DF set (mtu = 576)
From 1.2.3.4 (99.88.77.66) icmp_seq=1 Frag needed and DF set (mtu = 576)
From 1.2.3.4 (99.88.77.66) icmp_seq=1 Frag needed and DF set (mtu = 576)
From 1.2.3.4 (99.88.77.66) icmp_seq=1 Frag needed and DF set (mtu = 576)
--- core.myrelay.net ping statistics ---
0 packets transmitted, 0 received, +5 errors
}}
We received an ICMP message telling us the MTU is 576 bytes. The means we need to fragment the UDP packets smaller then 576 bytes to allow for some UDP overhead.
{{hc|# ping -c5 -M do -s 548 elmer.acmecorp.org|2=
PING elmer.acmecorp.org (99.88.77.66) 548(576) bytes of data.
556 bytes from 99.88.77.66: icmp_seq=1 ttl=48 time=206 ms
556 bytes from 99.88.77.66: icmp_seq=2 ttl=48 time=224 ms
556 bytes from 99.88.77.66: icmp_seq=3 ttl=48 time=206 ms
556 bytes from 99.88.77.66: icmp_seq=4 ttl=48 time=207 ms
556 bytes from 99.88.77.66: icmp_seq=5 ttl=48 time=208 ms
--- myrelay.net ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4001ms
rtt min/avg/max/mdev = 206.027/210.603/224.158/6.832 ms
}}
After some trial and error..., we discover that we need to fragment packets on 548 bytes. In order to do this we specify this fragment size in the configuration and instruct OpenVPN to fix the Maximum Segment Size (MSS).
{{hc|/etc/openvpn/client.conf|
remote elmer.acmecorp.org 1194
.
.
fragment 548
mssfix
.
.
user nobody
group nobody
.
.
ca /etc/openvpn/ca.crt
cert /etc/openvpn/bugs.crt
key /etc/openvpn/bugs.key
.
.
tls-auth /etc/openvpn/ta.key '''1'''
}}
{{Note|This will add about 3 minutes to OpenVPN start time. It is advisable to configure the fragment size unless your client is a laptop that will be connecting over many different networks and the bottle neck is on the client side.}}
You can also allow OpenVPN to do this for you by having OpenVPN do the ping testing every time the client connects to the VPN.
{{hc|/etc/openvpn/client.conf|
remote elmer.acmecorp.org 1194
.
.
mtu-test
.
.
user nobody
group nobody
.
.
ca /etc/openvpn/ca.crt
cert /etc/openvpn/bugs.crt
key /etc/openvpn/bugs.key
.
.
tls-auth /etc/openvpn/ta.key '''1'''
}}
== Starting OpenVPN ==
=== Manual startup ===
To troubleshoot a VPN connection, start the daemon manually with: {{ic|# openvpn /etc/openvpn/client.conf}}.
=== systemd service configuration ===
To start OpenVPN automatically at system boot, [[Daemon|enable]] {{ic|openvpn@''<configuration>''.service}}.
For example, if the configuration file is {{ic|/etc/openvpn/client.conf}}, the service name is {{ic|openvpn@client.service}}.
==== OpenVPN not restarting after suspend ====
{{accuracy|To avoid problems on systemd updates, modified configuration should be placed in [[Systemd#Writing_custom_.service_files|/etc/systemd/system/]].}}
If you put your system to sleep, on resume openvpn doesn't restart, which results in broken connectivity.
{{hc|/usr/lib/systemd/system-sleep/vpn.sh|2=
#!/bin/sh
if [ "$1" == "pre" ]
then
killall openvpn
fi
}}
Make it executable {{ic|chmod a+x /usr/lib/systemd/system-sleep/vpn.sh}}
Add {{ic|1=Restart=always}} to your {{ic|/usr/lib/systemd/system/openvpn@.service}}
== Advanced L3 IP routing==
=== Prerequisites for routing a LAN ===
==== IPv4 forwarding ====
For a host to be able to forward IPv4 packets between the LAN and VPN, it must be able to forward the packets between its NIC and its tun/tap device.
Edit or create {{ic|etc/sysctl.d/99-sysctl.conf}} to permanently enable IPv4 packet forwarding (takes effect at the next boot):
{{hc|/etc/sysctl.d/99-sysctl.conf|2=
# Enable packet forwarding
net.ipv4.ip_forward=1
}}
{{Tip|To temporarily enable without rebooting: {{ic|# echo 1 > /proc/sys/net/ipv4/ip_forward}}}}
==== Promiscuous LAN interface ====
The forwarding host's NIC (enp1s0 in the following examples) must also be able to accept packets for a different IP address than it is configured for, something known as [[Wikipedia:Promiscuous_mode|promiscuous mode]]. To set the {{ic|enp1s0}} in promiscuous mode using systemd, use [[ Network_configuration#Promiscuous_mode | this service file ]] and enable it using:
# systemctl enable promiscuous@enp1s0
{{Tip|To temporarily enable without rebooting: {{ic|# ip link set dev enp1s0 promisc on}}.}}
{{Note|I personally never needed to put any interfaces in promiscuous mode. A MASQUERADE rule should do the job.}}
==== Routing tables ====
{{Accuracy|Investigate if a routing protocol like RIP, QUAGGA, BIRD, etc can be used}}
By default, all IP packets on a LAN addressed to a different subnet get sent to the default gateway. If the LAN/VPN gateway is also the default gateway, there is no problem and the packets get properly forwarded. If not, the gateway has no way of knowing where to send the packets. There are a couple of solutions to this problem.
* Add a static route to the default gateway routing the VPN subnet to the LAN/VPN gateway's IP address.
* Add a static route on each host on the LAN that needs to send IP packets back to the VPN.
* Use [[iptables]]' NAT feature on the LAN/VPN gateway to masquerade the incoming VPN IP packets.
=== Connect the server LAN to a client ===
The server is on a LAN using the 10.66.0.0/24 subnet. To inform the client about the available subnet, add a push directive to the server configuration file:{{hc|/etc/openvpn/server.conf|push "route 10.66.0.0 255.255.255.0"}}
{{Note|
* Remember to enable IPv4 forwarding and to make the LAN interface promiscuous on the server. Make sure the server LAN knows how to reach the VPN client.
* To route more LANs from the server to the client, add more push directives to the server configuration file, but keep in mind that the server side LANs will need to know how to route to the client.
}}
=== Connect the client LAN to a server ===
Prerequisites:
* Any subnets used on the client side, must be unique and not in use on the server or by any other client. In this example we will use 192.168.4.0/24 for the clients LAN.
* Each client's certificate has a unique Common Name, in this case bugs.
* The server may not use the duplicate-cn directive in its config file.
Create a client configuration directory on the server. It will be searched for a file named the same as the client's common name, and the directives will be applied to the client when it connects.
# mkdir -p /etc/openvpn/ccd
Create a file in the client configuration directory called bugs, containing the {{ic|iroute 192.168.4.0 255.255.255.0}} directive. It tells the server what subnet should be routed to the client:
{{hc|/etc/openvpn/ccd/bugs|iroute 192.168.4.0 255.255.255.0}}
Add the client-config-dir and the {{ic|route 192.168.4.0 255.255.255.0}} directive to the server configuration file. It tells the server what subnet should be routed from the tun device to the server LAN:
{{hc|/etc/openvpn/server.conf|
client-config-dir ccd
route 192.168.4.0 255.255.255.0
}}
{{Note|
* Remember to enable IPv4 forwarding and to make the LAN interface promiscuous on the client. Make sure the client LAN knows how to reach the VPN server.
* To route more LANs from the client to the server, add more iroute and route directives to the appropriate configuration files, but keep in mind that the client side LANs will need to know how to route to the server.
}}
=== Connect both the client and server LANs ===
Combine the two previous sections:
{{hc|/etc/openvpn/server.conf|
push "route 10.66.0.0 255.255.255.0"
.
.
client-config-dir ccd
route 192.168.4.0 255.255.255.0
}}
{{hc|/etc/openvpn/ccd/bugs|iroute 192.168.4.0 255.255.255.0}}
{{Note|Remember to enable IPv4 forwarding and to make the LAN interfaces promiscuous on both the client and the server. Make sure that all the LANs or the needed hosts can route to all the destinations.}}
=== Connect clients and client LANs ===
By default clients will not see each other. To allow IP packets to flow between clients and/or client LANs, add a client-to-client directive to the server configuration file: {{hc|/etc/openvpn/server.conf|client-to-client}}
In order for another client or client LAN to see a specific client LAN, you will need to add a push directive for each client subnet to the server configuration file (this will make the server announce the available subnet(s) to other clients):
{{hc|/etc/openvpn/server.conf|
client-to-client
push "route 192.168.4.0 255.255.255.0"
push "route 192.168.5.0 255.255.255.0"
.
.
}}
{{Note|As always, make sure that the routing is properly configured.}}
== L2 Ethernet bridging ==
{{Expansion|Please add a well thought out section on L2 bridging.}}
For now see: [[OpenVPN Bridge]]
== Contributions that do not yet fit into the main article ==
{{Accuracy|Not quite sure where this fits into the main article yet}}
=== Routing client traffic through the server ===
Append the following to your server's openvpn.conf configuration file:
push "redirect-gateway def1"
push "dhcp-option DNS 192.168.1.1"
Change "192.168.1.1" to your preferred DNS IP address.
If you have problems with non responsive DNS after connecting to server, install [[BIND]] as simple DNS forwarder and push the IP address of the OpenVPN server as DNS to clients.
==== Configure ufw for routing ====
Configure your ufw settings to enable routing traffic from clients through server.
You must change default forward policy as in [[#IPv4 forwarding]].
And then configure ufw in {{ic|/etc/default/ufw}}:
{{hc|/etc/default/ufw|2=
DEFAULT_FORWARD_POLICY="ACCEPT"
}}
Now change {{ic|/etc/ufw/before.rules}}, and add the following code after the header and before the "*filter" line. Don't forget to change the IP/subnet mask to match the one in {{ic|/etc/openvpn/server.conf}}.
{{hc|/etc/ufw/before.rules|2=
# NAT (Network Address Translation) table rules
*nat
:POSTROUTING ACCEPT [0:0]
# Allow traffic from clients to enp1s0
-A POSTROUTING -s 10.8.0.0/8 -o enp1s0 -j MASQUERADE
# don't delete the "COMMIT" line or the NAT table rules above won't be processed
COMMIT
}}
Open OpenVPN port 1194:
ufw allow 1194
==== Using iptables ====
Use an iptable for NAT forwarding:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o enp1s0 -j MASQUERADE
If running Arch Linux in a OpenVZ VPS environment [http://thecodeninja.net/linux/openvpn-archlinux-openvz-vps/]:
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o venet0 -j SNAT --to (venet0 ip)
If all is well, make the changes permanent:
Edit {{ic|/etc/conf.d/iptables}} and change IPTABLES_FORWARD=1
# iptables-save > /etc/iptables/iptables.rules
=== Configuring LDAP authorization ===
{{Accuracy|what does the following do, and is the package still supported?}}
You may also want to install {{AUR|openvpn-authldap-plugin}}, available in the [[AUR]].
=== Deprecated older wiki content ===
{{Accuracy|See how this older content can be fitted into the new article}}
====Using PAM and passwords to authenticate====
{{bc|
port 1194
proto udp
mtu-test
dev tap
ca /etc/openvpn/easy-rsa/keys/ca.crt
cert /etc/openvpn/easy-rsa/keys/<MYSERVER>.crt
key /etc/openvpn/easy-rsa/keys/<MYSERVER>.key
dh /etc/openvpn/easy-rsa/keys/dh2048.pem
server 192.168.56.0 255.255.255.0
ifconfig-pool-persist ipp.txt
;learn-address ./script
client-to-client
;duplicate-cn
keepalive 10 120
;tls-auth ta.key 0
comp-lzo
;max-clients 100
;user nobody
;group nobody
persist-key
persist-tun
status /var/log/openvpn-status.log
verb 3
client-cert-not-required
username-as-common-name
plugin /usr/lib/openvpn/plugins/openvpn-plugin-auth-pam.so login
}}
==== Using certs to authenticate ====
{{bc|
port 1194
proto tcp
dev tun0
ca /etc/openvpn/easy-rsa/keys/ca.crt
cert /etc/openvpn/easy-rsa/keys/<MYSERVER>.crt
key /etc/openvpn/easy-rsa/keys/<MYSERVER>.key
dh /etc/openvpn/easy-rsa/keys/dh2048.pem
server 10.8.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt
keepalive 10 120
comp-lzo
user nobody
group nobody
persist-key
persist-tun
status /var/log/openvpn-status.log
verb 3
log-append /var/log/openvpn
status /tmp/vpn.status 10
}}
==== Routing traffic through the server ====
Append the following to your server's openvpn.conf configuration file:
push "dhcp-option DNS 192.168.1.1"
push "redirect-gateway def1"
Change "192.168.1.1" to your external DNS IP address.
Use an iptable for NAT forwarding:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o enp1s0 -j MASQUERADE
If running Arch Linux in a OpenVZ VPS environment [http://thecodeninja.net/linux/openvpn-archlinux-openvz-vps/]:
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o venet0 -j SNAT --to (venet0 ip)
If all is well, make the changes permanent:
Edit {{ic|/etc/conf.d/iptables}} and change IPTABLES_FORWARD=1
# iptables-save > /etc/iptables/iptables.rules
==== Setting up the client ====
The client-side .conf file
===== With password authentication =====
{{bc|
client
dev tap
proto udp
mtu-test
remote <address> 1194
resolv-retry infinite
nobind
persist-tun
comp-lzo
verb 3
auth-user-pass passwd
ca ca.crt
}}
passwd file (referenced by auth-user-pass) must contain two lines:
* first line - username
* second - password
===== Certificates authentication =====
{{bc|
client
remote <MYSERVER> 1194
dev tun0
proto tcp
resolv-retry infinite
nobind
persist-key
persist-tun
verb 2
ca ca.crt
cert client1.crt
key client1.key
comp-lzo
}}
Copy three files from server to remote computer.
ca.crt
client1.crt
client1.key
Install the tunnel/tap module:
# modprobe tun
To have the '''tun''' module loaded automatically at boot, read [[Kernel_modules]].
===== DNS =====
The DNS servers used by the system are defined in {{ic|/etc/resolv.conf}}. Traditionally, this file is the responsibility of whichever program deals with connecting the system to the network (e.g. Wicd, NetworkManager, etc...) However, OpenVPN will need to modify this file if you want to be able to resolve names on the remote side. To achieve this in a sensible way, install {{pkg|openresolv}}, which makes it possible for more than one program to modify resolv.conf without stepping on each-other's toes. Before continuing, test openresolv by restarting your network connection and ensuring that resolv.conf states that it was generated by "resolvconf", and that your DNS resolution still works as before. You should not need to configure openresolv; it should be automatically detected and used by your network system.
Next, save the following script at {{ic|/usr/share/openvpn/update-resolv-conf}}:
{{bc|<nowiki>
#!/bin/bash
#
# Parses DHCP options from openvpn to update resolv.conf
# To use set as 'up' and 'down' script in your openvpn *.conf:
# up /etc/openvpn/update-resolv-conf
# down /etc/openvpn/update-resolv-conf
#
# Used snippets of resolvconf script by Thomas Hood <jdthood@yahoo.co.uk>
# and Chris Hanson
# Licensed under the GNU GPL. See /usr/share/common-licenses/GPL.
# 07/2013 colin@daedrum.net Fixed intet name
# 05/2006 chlauber@bnc.ch
#
# Example envs set from openvpn:
# foreign_option_1='dhcp-option DNS 193.43.27.132'
# foreign_option_2='dhcp-option DNS 193.43.27.133'
# foreign_option_3='dhcp-option DOMAIN be.bnc.ch'
# foreign_option_4='dhcp-option DOMAIN-SEARCH bnc.local'
set -e
## You might need to set the path manually here, i.e.
# RESOLVCONF=/usr/bin/resolvconf
RESOLVCONF=$(which resolvconf)
[ -x $RESOLVCONF ] || exit 0
case $script_type in
up)
for optionname in ${!foreign_option_*} ; do
option="${!optionname}"
echo $option
part1=$(echo "$option" | cut -d " " -f 1)
if [ "$part1" == "dhcp-option" ] ; then
part2=$(echo "$option" | cut -d " " -f 2)
part3=$(echo "$option" | cut -d " " -f 3)
if [ "$part2" == "DNS" ] ; then
IF_DNS_NAMESERVERS="$IF_DNS_NAMESERVERS $part3"
fi
if [[ "$part2" == "DOMAIN" || "$part2" == "DOMAIN-SEARCH" ]] ; then
IF_DNS_SEARCH="$IF_DNS_SEARCH $part3"
fi
fi
done
R=""
for DS in $IF_DNS_SEARCH ; do
R="${R}search $DS
"
done
for NS in $IF_DNS_NAMESERVERS ; do
R="${R}nameserver $NS
"
done
#echo -n "$R" | $RESOLVCONF -p -a "${dev}"
echo -n "$R" | $RESOLVCONF -a "${dev}.inet"
;;
down)
$RESOLVCONF -d "${dev}.inet"
;;
esac
</nowiki>}}
Remember to make the file executable with:
$ chmod +x /usr/share/openvpn/update-resolv-conf
Next, add the following lines to your OpenVPN client configuration file:
script-security 2
up /usr/share/openvpn/update-resolv-conf
down /usr/share/openvpn/update-resolv-conf
Now, when your launch your OpenVPN connection, you should find that your resolv.conf file is updated accordingly, and also returns to normal when your close the connection.
''Caveat: The script will fail to restore the original DNS settings if your OpenVPN client.conf is set-up to drop root privileges after connection.''
===== Webmin =====
{{AUR|webmin-plugin-openvpn}} is available in the [[AUR]].
{{Note|You must add "openvpn" to the end of {{ic|/etc/webmin/webmin.acl}}.}}
==== Connecting to the server ====
You need to start the service on the server
systemctl start openvpn@server
To make it permanent:
systemctl enable openvpn@server
On the client, in the home directory create a folder that will hold your OpenVPN client config files along with the '''.crt'''/'''.key''' files. Assuming your OpenVPN config folder is called '''.openvpn''' and your client config file is '''vpn1.conf''', to connect to the server issue the following command:
# cd ~/.openvpn && openvpn vpn1.conf
== Troubleshooting ==
=== Resolve issues ===
If you are having resolve issues when starting your profile:
{{hc|# journalctl _SYSTEMD_UNIT=openvpn@''profile''.service|
RESOLVE: Cannot resolve host address: example.com: Name or service not known
}}
{{Accuracy|1=Ordering "After=network.target" does not work universally. See [http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/ network.target].}}
Then, '''only if your network setup can be started before OpenVPN''', you should force OpenVPN to wait for the network by adding {{ic|1=Requires=network.target}} and {{ic|1=After=network.target}} to the OpenVPN systemd service file:
{{hc|/usr/lib/systemd/system/openvpn@.service|<nowiki>
[Unit]
Description=OpenVPN connection to %i
Requires=network.target
After=network.target
...</nowiki>
}}
Don't forget to restart OpenVPN:
# systemctl daemon-reload
# systemctl restart openvpn@''profile''
== Ссылки ==
* [http://blog.gotux.net/code/ruby/vpnbook/ VPNBook Ruby Script (Free OpenVPN)]