OpenVPN – forward all client traffic through tunnel using UFW

By default OpenVPN only routes traffic to and from the OpenVPN Server. If you need all traffic from a client through the OpenVPN tunnel there are several options listed in the OpenVPN docs (http://openvpn.net/index.php/open-source/documentation/howto.html#redirect). Since I don't have any control over the server in some cases I needed a client side solution. As I already have ufw running with Ubuntu I wanted to use the existing software. Here is how to configure ufw to enable routing all traffic from your client machines through the OpenVPN Server. Forwarding policy Change default forward policy, edit /etc/sysctl.conf to permanently enable ipv4 packet forwarding. (Note: This will take effect at next boot). sudo vim /etc/sysctl.conf # Enable packet forwarding net.ipv4.ip_forward=1 UFW config And then configure ufw in /etc/default/ufw sudo vim /etc/default/ufw DEFAULT_FORWARD_POLICY="ACCEPT" UFW before rules Change /etc/ufw/before.rules to add the following code after the header and before the "*filter" line. Match the IP/subnet mask to the same one as in /etc/openvpn/server.conf. sudo vim /etc/ufw/before.rules # START OPENVPN RULES # NAT table rules *nat :POSTROUTING ACCEPT [0:0] # Allow traffic from OpenVPN client to eth0 -A POSTROUTING -s 10.8.0.0/8 -o eth0 -j MASQUERADE COMMIT # END OPENVPN RULES Enable OpenVPN Open openvpn port 1194 sudo ufw allow 1194 Start UFW sudo service ufw start

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OpenVPN Install on CentOS 6 Server

I recently had a need to install a VPN service in a OpenVZ container. Since I normally only use Hardware emulating VM's I ran into quite a few issues in terms of low-level networking support on this Container Virtualisation System. Turns out that you are stuck with a TUN/TAP solution as most services won't enable PPP services on their infrastructure. Also Ethernet bridging is not available (at least on the service I used) so you're stuck with NAT IP masquerading. Considering the options I thought best served with using OpenVPN server. Install Server yum --enablerepo=epel -y install openvpn Server configuration cp /usr/share/doc/openvpn-*/sample-config-files/server.conf /etc/openvpn/ These are the contents of /etc/openvpn/server.conf local XXX.XXX.XXX.XXX #Server External IP port 1194 proto udp dev tun ca ca.crt cert SERVER.crt key SERVER.key #keep file secret dh dh1024.pem server 10.8.0.0 255.255.255.0 ifconfig-pool-persist ipp.txt push "redirect-gateway def1 bypass-dhcp" push "dhcp-option DNS 8.8.8.8" #using Google Public DNS push "dhcp-option DNS 8.8.4.4" #using Google Public DNS keepalive 10 120 comp-lzo max-clients 5 user nobody group nobody persist-key persist-tun status openvpn-status.log log /var/log/openvpn.log verb 3 mkdir -p /etc/openvpn/easy-rsa/keys cd /etc/openvpn/easy-rsa cp -rf /usr/share/openvpn/easy-rsa/2.0/* . vim vars #Set the country (KEY_COUNTRY) #state (KEY_PROVINCE) #locality (KEY_CITY) #organisation name (KEY_ORG) #support email (KEY_EMAIL) Create certificate authority ./vars ./clean-all ./build-ca The CA key and certificate should not be in the keys directory inside the easy-rsa directory. Create certificate for the server ./build-key-server NAME_OF_SERVER Answer the questions and commit the certificate into the database Create the Diffie Hellman files These files are used for the actual…

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