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Issues with initial bridge setup

Posted: Fri Sep 02, 2011 6:06 pm
by nanotronicsimaging
I have recently installed OVPN to ubuntu 11.04 . The server has set up correctly and clients are able to connect, however they are not able to ping across the tunnel nor are they able to access the windows file shares on the LAN. I do have samba and likewise installed so that the Linux machine is part of the AD. I have a feeling the issues lies within the bridging of the devices. Any help would be greatly appreciated.

Re: Issues with initial bridge setup

Posted: Mon Sep 05, 2011 8:14 am
by maikcat
hi there,

please post more info about your setup (configs,logs etc).

Michael.

Re: Issues with initial bridge setup

Posted: Tue Sep 06, 2011 1:10 pm
by nanotronicsimaging
Right, sorry about that!

Server config file
# Which local IP address should OpenVPN
# listen on? (optional)
local 192.168.11.5

# 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 tap0


# 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 easy-rsa/keys/ca.crt
cert easy-rsa/keys/server.crt
key easy-rsa/keys/server.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 easy-rsa/keys/dh1024.pem

# Configure server mode and supply a VPN subnet
# for OpenVPN to draw client addresses from.
# The server will take 10.8.0.1 for itself,
# the rest will be made available to clients.
# Each client will be able to reach the server
# on 10.8.0.1. Comment this line out if you are
# ethernet bridging. See the man page for more info.
server 192.168.2.0 255.255.255.0

# 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 10.8.0.4/255.255.255.0. Finally we
# must set aside an IP range in this subnet
# (start=10.8.0.50 end=10.8.0.100) to allocate
# to connecting clients. Leave this line commented
# out unless you are ethernet bridging.
;server-bridge 192.168.11.5 255.255.255.0 192.168.11.55 192.168.11.100

# 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 (10.8.0.0/255.255.255.0)
# back to the OpenVPN server.
push "route 192.168.11.1 255.255.255.0"
;push "route 192.168.20.0 255.255.255.0"

# 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
# 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 192.168.11.230"
;push "dhcp-option DNS 192.168.11.1"

# 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

# 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

# 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 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


bridge start file

#!/bin/bash
# Create global variables
# 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="192.168.11.5"
eth_netmask="255.255.255.0"
eth_broadcast="192.168.11.255"
gw="192.168.11.1"
start_bridge () {
#################################
# Set up Ethernet bridge on Linux
# Requires: bridge-utils
#################################
for t in $tap; do
openvpn --mktun --dev $t
done
for t in $tap; do
ifconfig $t 0.0.0.0 promisc up
done
ifconfig $eth 0.0.0.0 promisc up
brctl addbr $br
brctl addif $br $eth
for t in $tap; do
brctl addif $br $t
done
ifconfig $br $eth_ip netmask $eth_netmask broadcast

networking interfacess file

auto lo
iface lo inet loopback

Re: Issues with initial bridge setup

Posted: Wed Sep 07, 2011 9:14 am
by maikcat
here is server conf stripped from comments..

local 192.168.11.5
port 1194
proto udp
dev tap0
ca easy-rsa/keys/ca.crt
cert easy-rsa/keys/server.crt
key easy-rsa/keys/server.key # This file should be kept secret
dh easy-rsa/keys/dh1024.pem
server 192.168.2.0 255.255.255.0
ifconfig-pool-persist ipp.txt
push "dhcp-option DNS 192.168.11.230"
client-to-client
keepalive 10 120
comp-lzo
user nobody
group nogroup
persist-key
persist-tun
status openvpn-status.log
verb 3


your config is for routing NOT bridging.. (server directive)

if you want bridging comment server directive and replace with

server-bridge 192.168.11.5 255.255.255.0 192.168.11.100 192.168.11.110 <--100 to 110 is ip range for clients

also you must enable ip forwarding
for testing i recommend disabling iptables

also remove : push "route 192.168.11.1 255.255.255.0" if you use bridging
if you use routing use

push "route 192.168.11.0 255.255.255.0"

what setup is more suitable for you routing or bridging?

Michael.

Re: Issues with initial bridge setup

Posted: Wed Sep 07, 2011 12:15 pm
by nanotronicsimaging
I believe it needs to be bridged because I need my employees who are off site to be able to vpn in and access the files as though they were here on the local LAN. I have changed some of the config files and will post them for you. I believe that I also already have ip forwarding enabled. I am using the syswan duolinks sw24 as the router/switch.

local 192.168.11.5
port 1194
proto udp
dev tap0
ca easy-rsa/keys/ca.crt
cert easy-rsa/keys/server.crt
key easy-rsa/keys/server.key # This file should be kept secret
dh easy-rsa/keys/dh1024.pem
ifconfig-pool-persist ipp.txt
server-bridge 192.168.11.5 255.255.255.0 192.168.11.55 192.168.11.100
push "route 192.168.11.1 255.255.255.0"
client-to-client
keepalive 10 120
comp-lzo
user nobody
group nogroup
persist-key
persist-tun
status openvpn-status.log
verb 3
;mute 20

Re: Issues with initial bridge setup

Posted: Wed Sep 07, 2011 12:17 pm
by nanotronicsimaging
I also commented out the push route line

Re: Issues with initial bridge setup

Posted: Wed Sep 07, 2011 1:34 pm
by maikcat
if you want to simply access (via smb for example) resources
routing is better choice..

simply push a route to your clients with your local lan,
and configure routing accordingly and will work...

bridging is not the optimal way to connect road warriors to your network..

Michael.

Re: Issues with initial bridge setup

Posted: Wed Sep 07, 2011 2:57 pm
by nanotronicsimaging
Ok so with the routing I will add the push routes, then configure the static routing? What would that server config file look like? Will this give them access to everything within the network here by name?

Re: Issues with initial bridge setup

Posted: Thu Sep 08, 2011 1:35 pm
by maikcat
server config

local 192.168.11.5
port 1194
proto udp
dev tun
ca easy-rsa/keys/ca.crt
cert easy-rsa/keys/server.crt
key easy-rsa/keys/server.key # This file should be kept secret
dh easy-rsa/keys/dh1024.pem
ifconfig-pool-persist ipp.txt
push "route 192.168.11.0 255.255.255.0"
server 10.8.0.0 255.255.255.0
client-to-client
keepalive 10 120
comp-lzo
user nobody
group nogroup
persist-key
persist-tun
status openvpn-status.log
verb 3


your first client will get 10.8.0.6 ip
you must enable ip forwarding to your server
you must configure lan pcs firewall to allow access from 10.8.0 net

change your client config to dev tun

Michael.

Re: Issues with initial bridge setup

Posted: Thu Sep 08, 2011 6:52 pm
by nanotronicsimaging
Thank you sir, so then i would add a static route for the routing as

Static Routing
Network Address Subnet Mask Gateway Interface Metric Route Mode
(2~15)


Routing List
Destination IP Subnet Mask Gateway Interface Metric Route Mode Type
10.8.0.1 255.255.255.0 192.168.11.1 LAN 2 Transport Manual



???

Re: Issues with initial bridge setup

Posted: Fri Sep 09, 2011 2:01 pm
by nanotronicsimaging
Still didnt work, not sure if I am doing something wrong?? I can ping the host computer but nothing else on the network

Re: Issues with initial bridge setup

Posted: Mon Sep 12, 2011 8:50 am
by maikcat
try executing the following into one of your windows pc inside your lan

route add 10.8.0.0 mask 255.255.255.0 192.168.11.5 -p


then try to ping 10.8.0.6 (your vpn client)
also

you must enable ip forwarding on your openvpn server
and configure firewall on openvpn server & openvpn client accordingly

Michael.

Re: Issues with initial bridge setup

Posted: Mon Sep 12, 2011 12:49 pm
by nanotronicsimaging
Ok sorry if I sound like a total newb. I have very little experience with Linux. In order to enable the ip forwarding on the ubuntu machine that is running the openvpn, how exactly do I do this?? Thanks for all your help so far.

Re: Issues with initial bridge setup

Posted: Mon Sep 12, 2011 1:32 pm
by nanotronicsimaging
Also,
Will this method enable my workers to connect as if they were right within the office on the LAN?

Re: Issues with initial bridge setup

Posted: Tue Sep 13, 2011 9:23 am
by maikcat
to enable ip forwarding edit /etc/sysctl.conf

net.ipv4.ip_forward = 0

to

net.ipv4.ip_forward = 1

save the file and

sysctl -p

and you have enabled it
>Will this method enable my workers to connect as if they were right within the office on the LAN?

you will gain ip connectivity with your lan...
but some type of traffic will be filtered out (broadcasts),
what type of connectivity exactly are you seeking?

Michael.

Re: Issues with initial bridge setup

Posted: Tue Sep 13, 2011 1:29 pm
by nanotronicsimaging
I basically need the employees to be able to connect and have access to all the files as if they were here within the network but from anywhere in the world. I also need them to have host name resolution from the dns

Re: Issues with initial bridge setup

Posted: Wed Sep 14, 2011 8:08 am
by maikcat
you can also push dns server ip to your clients as well,

i believe routing mode is ok for you...

Michael.

Re: Issues with initial bridge setup

Posted: Wed Sep 14, 2011 1:09 pm
by nanotronicsimaging
I have set everything as you asked, however it is still not working. Would you like some of the error logs?

Re: Issues with initial bridge setup

Posted: Thu Sep 15, 2011 8:12 am
by maikcat
sure post them...

also please post output of netstat -nr from :openvpn server,openvpn client,a pc inside your lan.

also ping from your client:

the ip of vpn server (virtual interface)
the lan ip of vpn server
a pc inside your network

Michael.

Re: Issues with initial bridge setup

Posted: Thu Sep 15, 2011 12:43 pm
by nanotronicsimaging
I basically need them to be able to still access the internet from their machines, but also have the ability to see all hosts and computers within the local network here as if they were plugged into our lan. Needs to have name resolution.