Howto/Setup Bridged OpenVPN server on Ubuntu 10.04
I want my users to be able to access my network remotely as if they were locally. Also, I want client side configuration steps kept to a minimum. Specifically, I want clients to use the "alternative OpenVPN authentication method". Also, I want clients to be able to see all machines on the server's side (this last bit was what cost me a LOT of time to figure out). Last but not least, I do NOT want all traffic being forwarded through the VPN.
- The following was tested on OpenVPN 2.1 but may work for other version
- I have a standard router that acts as my gateway, located at 192.168.8.1
- My OpenVPN server has one NIC on eth0 and its ip address is 192.168.8.141 and it is using the default UDP 1194 port
- My router is setup to assign ip addresses upon requests via dhcp in the range 192.168.8.100 to 192.168.8.199, and my servers have static leases.
- The OpenVPN server will be responsible for handing out ips to clients in the range 192.168.8.5 to 192.168.8.99
Using the following as a guide,
https://help.ubuntu.com/lts/serverguide/openvpn.html https://help.ubuntu.com/10.04/serverguide/C/openvpn.html https://help.ubuntu.com/10.04/serverguide/C/network-configuration.html#bridging
- Step 1) Install prerequisites
sudo apt-get install openvpn bridge-utils easy-rsa
- Step 2) Install a virtual bridged adapter
# The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet manual # bridge, if router can lease static ips (static ip: 192.168.8.141) auto br0 iface br0 inet dhcp bridge_ports eth0 bridge_fd 9 bridge_hello 2 bridge_maxage 12 bridge_stp off ## bridge, if router cannot lease static ips #auto br0 #iface br0 inet static # address 192.168.8.141 # network 192.168.8.0 # netmask 255.255.255.0 # broadcast 192.168.8.255 # gateway 192.168.8.1 # bridge_ports eth0 # bridge_fd 9 # bridge_hello 2 # bridge_maxage 12 # bridge_stp off
sudo /etc/init.d/networking restart
- Step 3) Create the server certificates
Follow the directions
- Step 4) Configure the server
Note: Do not create client certificates as we wish to only authenticate with a username and password as per the instructions at http://openvpn.net/index.php/open-source/documentation/howto.html#auth Specifically, start by getting a sample config file
sudo cp /usr/share/doc/openvpn/examples/sample-config-files/server.conf.gz /etc/openvpn/ sudo gzip -d /etc/openvpn/server.conf.gz
Then modify the server.conf
local 192.168.8.141 dev tap0 ;dev tun ;server 10.8.0.0 255.255.255.0 server-bridge 192.168.8.141 255.255.255.0 192.168.8.5 192.168.8.99 push "route 192.168.8.0 255.255.255.0" push "dhcp-option DNS 192.168.8.1" client-to-client duplicate-cn ;tls-auth ta.key 0 user nobody group nogroup plugin /usr/lib/openvpn/openvpn-auth-pam.so login client-cert-not-required username-as-common-name up "/etc/openvpn/up.sh br0" down "/etc/openvpn/down.sh br0" push "ip-win32 dynamic 0 3600"
Create the up.sh and down.sh scripts as per the Ubuntu guide
place them in /etc/openvpn and make them executable
sudo chmod 755 /etc/openvpn/down.sh sudo chmod 755 /etc/openvpn/up.sh
Here was the part that took me MANY HOURS to figure out as it was only by browsing the OpenVPN FAQ that I figured it out. For clients to see all machines on the server's side, edit /etc/sysctl.conf
Restart the server for changes to take effect.
- Step 5) Forward ports on the router
Forward requests for port 1194 on the router to the ip address of the server via the router's web interface.
- Step 6) On another machine outside the network, install the client
For Ubuntu it is already installed after doing
sudo apt-get install openvpn
For Windows, get the complete installation package here
- Step 6) Configure the client
Get a sample config file. On Ubuntu, it is located here
and, if run as a daemon, it must be placed in /etc/openvpn along with the ca.crt file that was generated in Step 3.
On Windows, it is located at
and it must be placed in
along with the ca.crt file that was generated in Step 3. Modify the following lines in client.conf or client.opvn
dev tap ;dev tun remote www.interpause.com 1194 user nobody group nobody ;cert client.crt ;key client.key ;tls-auth ta.key 1 auth-user-pass
- Step 7) Start the client
On Ubuntu, it can be started as a daemon or at the command prompt using
sudo openvpn --config client.conf
On Windows, reload the GUI and there should be a Connect option that appears if the config file and the ca.crt certificate and in the correct place.
You should be able to ping and access any shares located on the server's side.
- Troubleshooting Tip
On an Ubuntu server and client, instead of running the server (and client) as a daemon, execute it at the command prompt using
sudo openvpn --config server.conf --script-security 2
and observe the output.