Ubuntu – Need help setting up OpenVPN on an Ubuntu server

EDIT:

OK, thanks to all of your help I've made some progress. I fixed the connectivity issues with the bridge by manually setting up the bridge in the interfaces file and editing the bridge-start and bridge-stop scripts to only add/take-down the tap interface (See bellow for the current versions of these files.)

Now I can connect to the server, but the connection keeps getting dropped. Is this a key issue? I've tried regenerating the keys to no avail.

The log from Tunnelbrick when trying to connect to my server:

2010-09-19 10:08:05 *Tunnelblick: OS X 10.6.4; Tunnelblick 3.0 (build 1437); OpenVPN 2.1.1
2010-09-19 10:08:07 *Tunnelblick: Attempting connection with evan's apartment.conf; Set nameserver = 1; monitoring connection
2010-09-19 10:08:07 *Tunnelblick: /Applications/Tunnelblick.app/Contents/Resources/openvpnstart start evan's\ apartment.conf 1338 1 0 0 0
2010-09-19 10:08:07 *Tunnelblick: /Applications/Tunnelblick.app/Contents/Resources/openvpn --management-query-passwords --cd /Users/evan/Library/Application Support/Tunnelblick/Configurations --daemon --management-hold --management 127.0.0.1 1338 --config /Users/evan/Library/Application Support/Tunnelblick/Configurations/evan's apartment.conf --script-security 2 --up "/Applications/Tunnelblick.app/Contents/Resources/client.up.osx.sh" --down "/Applications/Tunnelblick.app/Contents/Resources/client.down.osx.sh" --up-restart
2010-09-19 10:08:07 SUCCESS: pid=2376
2010-09-19 10:08:07 SUCCESS: real-time state notification set to ON
2010-09-19 10:08:07 SUCCESS: real-time log notification set to ON
2010-09-19 10:08:07 OpenVPN 2.1.1 i386-apple-darwin10.2.0 [SSL] [LZO2] [PKCS11] built on Feb 24 2010
2010-09-19 10:08:07 MANAGEMENT: TCP Socket listening on 127.0.0.1:1338
2010-09-19 10:08:07  waiting...
2010-09-19 10:08:07 MANAGEMENT: Client connected from 127.0.0.1:1338
2010-09-19 10:08:07 MANAGEMENT: CMD 'pid'
2010-09-19 10:08:07 MANAGEMENT: CMD 'state on'
2010-09-19 10:08:07 MANAGEMENT: CMD 'log on all'
2010-09-19 10:08:07 END
2010-09-19 10:08:07 MANAGEMENT: CMD 'hold release'
2010-09-19 10:08:07 SUCCESS: hold release succeeded
2010-09-19 10:08:07 NOTE: the current --script-security setting may allow this configuration to call user-defined scripts
2010-09-19 10:08:07 Control Channel Authentication: using '/Users/evan/VPN/ta.key' as a OpenVPN static key file
2010-09-19 10:08:07 Outgoing Control Channel Authentication: Using 160 bit message hash 'SHA1' for HMAC authentication
2010-09-19 10:08:07 Incoming Control Channel Authentication: Using 160 bit message hash 'SHA1' for HMAC authentication
2010-09-19 10:08:07 LZO compression initialized
2010-09-19 10:08:07 Control Channel MTU parms [ L:1576 D:168 EF:68 EB:0 ET:0 EL:0 ]
2010-09-19 10:08:07 Data Channel MTU parms [ L:1576 D:1450 EF:44 EB:135 ET:32 EL:0 AF:3/1 ]
2010-09-19 10:08:07 Local Options hash (VER=V4): 'e39a3273'
2010-09-19 10:08:07 Expected Remote Options hash (VER=V4): '3c14feac'
2010-09-19 10:08:07  or --up-delay
2010-09-19 10:08:07 Attempting to establish TCP connection with 192.168.0.2:1194 [nonblock]
2010-09-19 10:08:07 
2010-09-19 10:08:08 TCP connection established with 192.168.0.2:1194
2010-09-19 10:08:08 Socket Buffers: R=[525624->65536] S=[131768->65536]
2010-09-19 10:08:08 TCPv4_CLIENT link local: [undef]
2010-09-19 10:08:08 TCPv4_CLIENT link remote: 192.168.0.2:1194
2010-09-19 10:08:08 
2010-09-19 10:08:08  restarting [0]
2010-09-19 10:08:08 TCP/UDP: Closing socket
2010-09-19 10:08:08  process restarting
2010-09-19 10:08:08 
2010-09-19 10:08:08 MANAGEMENT: CMD 'hold release'
2010-09-19 10:08:08 SUCCESS: hold release succeeded
2010-09-19 10:08:08 NOTE: the current --script-security setting may allow this configuration to call user-defined scripts
2010-09-19 10:08:08 Re-using SSL/TLS context
2010-09-19 10:08:08 LZO compression initialized
2010-09-19 10:08:08 Control Channel MTU parms [ L:1576 D:168 EF:68 EB:0 ET:0 EL:0 ]
2010-09-19 10:08:08 Data Channel MTU parms [ L:1576 D:1450 EF:44 EB:135 ET:32 EL:0 AF:3/1 ]
2010-09-19 10:08:08 Local Options hash (VER=V4): 'e39a3273'
2010-09-19 10:08:08 Expected Remote Options hash (VER=V4): '3c14feac'
2010-09-19 10:08:08 Attempting to establish TCP connection with 192.168.0.2:1194 [nonblock]
2010-09-19 10:08:08 
2010-09-19 10:08:09 TCP connection established with 192.168.0.2:1194
2010-09-19 10:08:09 Socket Buffers: R=[525624->65536] S=[131768->65536]
2010-09-19 10:08:09 TCPv4_CLIENT link local: [undef]
2010-09-19 10:08:09 TCPv4_CLIENT link remote: 192.168.0.2:1194
2010-09-19 10:08:09 
2010-09-19 10:08:09  restarting [0] ... (just keeps repeating from here)

Here are the updated files that I've changed:

interfaces

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.0.2
netmask 255.255.255.0
gateway 192.168.0.1

# Bridge for OpenVPN
auto br0
iface br0 inet static
address 192.168.0.2
netmask 255.255.255.0
gateway 192.168.0.1
bridge_ports eth0

bridge-start

#!/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="192.168.0.2"
eth_netmask="255.255.255.0"
eth_broadcast="192.168.0.255"
eth_gateway="192.168.0.1"
eth_network="192.168.0.0"

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 gateway $eth_gateway

bridge-stop

#!/bin/bash

####################################
# Tear Down Ethernet bridge on Linux
####################################

# Define Bridge Interface
br="br0"

# Define list of TAP interfaces to be bridged together
tap="tap0"

#ifconfig $br down
#brctl delbr $br

for t in $tap; do
    openvpn --rmtun --dev $t
done

My server.conf file look like the one aleroot suggested.

Thanks for all of your help so far, I think I'm close now :).

ORIGINAL QUESTION:

I'm trying to get my Ubuntu 10.04 server to act as an OpenVPN server so I can eventually samba mount my data on my labtop while I'm at work. I've followed the instructions here a few times now with no luck.

I'm fairly certain the problem has to do with setting up the bridges and the tap interface. The reason I think that is because once I set up the bridge (using these scripts – http openvpn.net/index.php/open-source/documentation/miscellaneous/76-ethernetbridging.html#linuxscript – sorry I can only make one link at the moment :)) and start the server (which starts with no errors) I'm loosing my eth0 connection ( and when I run ifconfig, only the new br0 has an IP address). Also after enabling the bridges I can no longer ssh to my server which starts working again when I stop the openvpn server and run the bridge-stop script.

I think I'm confused about which IP address goes where.

My router has public IP address, lets say it's 25.25.25.25 and my Ubuntu server has a static ip address of 192.168.0.2 (the port forwarding and everything works correctly, I can ssh in from anywhere, until I run the bridge scripts or try :)). Here are the values I've been using in the files specified above, do they look right?

From bridge-start (link to full file above)

# Define physical ethernet interface to be bridged
# with TAP interface(s) above.
eth="eth0"
eth_ip="192.168.0.2"
eth_netmask="255.255.255.0"
eth_broadcast="192.168.0.255"

From server.conf

local 192.168.0.2
dev tap0
up "/etc/openvpn/up.sh br0"
down "/etc/openvpn/down.sh br0"
;server 10.8.0.0 255.255.255.0
server-bridge 192.168.0.2 255.255.255.0 192.168.0.50 192.168.100
push "route 192.168.0.2 255.255.255.0"
push "dhcp-option DNS 192.168.0.1"
;push "dhcp-option DOMAIN example.com" <- commented not sure what i should use, the value is resolve.conf?
tls-auth ta.key 0 # This file is secret
user nobody
group nogroup

Thanks for your help!!