OpenVPN and bridge interface configuration

Question

I am trying to configure a VPN under Ubuntu and openVPN. I have followed this guide: https://help.ubuntu.com/10.04/serverguide/C/openvpn.html but I can't conect from any client, I always get a timeout error.

In my opinion, the problem is located in the bridge configuration. According to Ubuntu wiki, I should configure a bridge interface this way:

auto lo 
iface lo inet loopback 

auto br0 
iface br0 inet static 
address 192.168.0.10 
network 192.168.0.0 
netmask 255.255.255.0 
broadcast 192.168.0.255 
gateway 192.168.0.1 
bridge_ports eth0 
bridge_fd 9 
bridge_hello 2 
bridge_maxage 12 
bridge_stp off

But I am not sure about the values I have to assign to adress, network, netmask, broadcast and gateway.

The output of ifconfig is the following one (the IP is not real):

eth0 Link encap:Ethernet HWaddr 00:19:99:14:01:d1 
inet addr:87.106.179.10 Bcast:87.106.179.10 Mask:255.255.255.255 
inet6 addr: fe80::219:99ff:fe14:1d1/64 Scope:Link 
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 
RX packets:1147011 errors:1 dropped:0 overruns:0 frame:1 
TX packets:2052888 errors:0 dropped:0 overruns:0 carrier:0 
collisions:0 txqueuelen:1000 
RX bytes:78775595 (78.7 MB) TX bytes:2585422360 (2.5 GB) 
Interrupt:20 Base address:0xa000 

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:5040278 errors:0 dropped:0 overruns:0 frame:0 
TX packets:5040278 errors:0 dropped:0 overruns:0 carrier:0 
collisions:0 txqueuelen:0 
RX bytes:1991710982 (1.9 GB) TX bytes:1991710982 (1.9 GB)

My server is a dedicated one; mi local IP, the public IP and the broadcast are the same. I do not know if this is common in a dedicated server.

My current /etc/network/interfaces is the following one:

auto lo 
iface lo inet loopback 

auto eth0 
iface eth0 inet dhcp 

auto br0 
iface br0 inet static 
address 87.106.179.10
network 192.168.0.0 
netmask 255.255.255.0 
broadcast 192.168.0.255 
gateway 87.106.179.10
bridge_ports eth0 
bridge_fd 9 
bridge_hello 2 
bridge_maxage 12 
bridge_stp off

Maybe the problem is anywhere else but I am not sure about this file being correct.

I would appreciate any kind of help, thank you in advance.

score 1 · Answer 1 · answered Nov 04 '10 at 15:09

To setup the brige you could use this code:

http://openvpn.net/index.php/open-source/documentation/miscellaneous/76-ethernet-bridging.html#linuxscript

 #!/bin/bash
 #################################
 #Set up Ethernet bridge on Linux# 
 Requires: bridge-utils
 ################################# 

 #Define Bridge Interface
 br="br0"

 # Define list of TAP interfaces to be bridged,
 # for example tap="tap0 tap1 tap2".
 tap="tap0"

 # Define physical ethernet interface to be bridged
 # with TAP interface(s) above.
 eth="eth0"
 eth_ip="192.168.8.4"
 eth_netmask="255.255.255.0"
 eth_broadcast="192.168.8.255"
 for t in $tap; do    
    openvpn --mktun --dev $t
 done
 brctl addbr $br
 brctl addif $br $eth
 for t in $tap; do
     brctl addif $br $t
 done
 for t in $tap; do
     ifconfig $t 0.0.0.0 promisc up
 done
 ifconfig $eth 0.0.0.0 promisc up
 ifconfig $br $eth_ip netmask $eth_netmask broadcast $eth_broadcast

you should use the address of your local network.

post your full configuration of client and server so i can help you further, also, what does the connection log says? is it a problem negotiating the tunnel?, is the public IP being forwarded to the OpenVPN server?

Regards,
Hugo

OpenVPN and bridge interface configuration

1 Answers1