OpenWrt

1. Install the openvpn package:

opkg update
opkg install openvpn

opkg update
opkg install openvpn luci-app-openvpn

1. open the firewall file

vi /etc/config/firewall

1. towards the bottom append change the dest_port variable to your preference:

config 'rule'
        option 'target' 'ACCEPT'
        option 'dest_port' '1194'
        option 'src' 'wan'
        option 'proto' 'tcpudp'
        option 'family' 'ipv4'

1. restart the network filter

/etc/init.d/network restart

Edit /etc/config/openvpn to fit your need.

vi /etc/config/openvpn

The following is a example. There are multiple examples included in the configuration file.

option 'port' '1194'
option 'proto' 'udp'
option 'dev' 'tun'
option 'ca' '/etc/openvpn/ca.crt'
option 'cert' '/etc/openvpn/server.crt'
option 'key' '/etc/openvpn/server.key'
option 'dh' '/etc/openvpn/dh.pem'
option 'tls_auth' '/etc/openvpn/shared.key 0'
option 'server' '10.8.0.0 255.255.255.0'
list 'push' 'route 192.168.1.0 255.255.255.0'
list 'push' 'redirect-gateway"'
option 'comp_lzo'
option 'keepalive' '10 120'
option 'status' '/tmp/openvpn.status'

There is a bug in the /etc/init.d/openvpn. the push directives to openvpn should be encapsulated with double quotes ("), but the init script uses single quotes ('). If you want the push directives to work with openvpn you should modify the init script lines 103 and 107 to look like.

There is a ticket about this ( https://dev.openwrt.org/ticket/10518 ). It has been fixed upstream but it has not hit any of the stable releases yet. — sup 2012/05/07 12:16

tun_mtu tun_mtu_extra txqueuelen user verb push

        # append multi-value params
        append_params_quoted "$s" \
                down up