I set up an OpenVPN server using Ubuntu and a windows server 2003 client to interconnect two networks between two different offices. They can now ping each other, but the rest of the network cannot be contacted by the windows client.

Office 1 has internal network of:

192.168.0.0 255.255.240.0

Office 2 has internal network of:

192.168.16.0 255.255.255.0

And the configuration files are:

Server.conf

port 1194
--script-security 2
up "/etc/openvpn/up.sh br0"
down "/etc/openvpn/down.sh br0"

# TCP or UDP server?
;proto tcp
proto udp

dev tap0
;dev tun

ca ca.crt
cert openvpn.crt
key openvpn.key

dh dh1024.pem
ifconfig-pool-persist ipp.txt
server-bridge 192.168.0.59 255.255.240.0 192.168.6.72 192.168.6.75
push "route 192.168.0.0 255.255.240.0"

push "dhcp-option DNS 192.168.0.2"
push "dhcp-option DOMAIN testeers.local"
keepalive 10 120

tls-auth ta.key 0 # This file is secret

comp-lzo
user nobody
group nogroup
persist-key
persist-tun

log   /var/log/openvpn/openvpn.log
status /var/log/openvpn-status.log

verb 3

Client Config file

client
dev tap
;dev tun
--script-security 2
;proto tcp
proto udp
remote 1xx.2xx.xxx.124 1194
resolv-retry infinite
nobind
persist-key
persist-tun

ca ca.crt
cert admin-VAIO.crt
key admin-VAIO.key

ns-cert-type server

tls-auth ta.key 1

comp-lzo
verb 3

Ifconfig on the server now shows the following:

br0       Link encap:Ethernet  HWaddr 00:50:56:8b:1a:49
          inet addr:192.168.0.59  Bcast:192.168.15.255  Mask:255.255.240.0
          inet6 addr: fe80::250:56ff:fe8b:1a49/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1081860 errors:0 dropped:1358 overruns:0 frame:0
          TX packets:242385 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:76600615 (76.6 MB)  TX bytes:64474575 (64.4 MB)

eth0      Link encap:Ethernet  HWaddr 00:50:56:8b:1a:49
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:1144125 errors:0 dropped:7172 overruns:0 frame:0
          TX packets:252486 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:109893729 (109.8 MB)  TX bytes:66372620 (66.3 MB)

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:67865 errors:0 dropped:0 overruns:0 frame:0
          TX packets:67865 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:5183276 (5.1 MB)  TX bytes:5183276 (5.1 MB)

tap0      Link encap:Ethernet  HWaddr 32:4f:42:11:b7:c5
          inet6 addr: fe80::304f:42ff:fe11:b7c5/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:3329 errors:0 dropped:0 overruns:0 frame:0
          TX packets:215472 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:373205 (373.2 KB)  TX bytes:17465832 (17.4 MB)