VPN kill switch on DD-WRT and OpenVPN

Question

I followed the DD-WRT: VPN OpenVPN Setup to configure the VPN connection on my router. Apparently i use privateinternetaccess as a VPN provider and OpenVPN. It works fine, but there is no VPN kill switch! Is there any way to implement it?

Answer 1

You will need to ssh/telnet into the router and perform the following command:

 killall openvpn

If you need to restart the vpn, the command would be something like:

 openvpn --config <location of your client.conf>

Answer 2

Under Administration --> Commands copy-paste the following and press "Save Firewall".

# --- SEAMLESS TUNNEL ---
# http://www.dd-wrt.com/phpBB2/viewtopic.php?p=957052
if [ "$(nvram get wan_proto)" == "pppoe" ]; then
    WAN_IF="$(nvram get pppoe_ifname)"
elif [ "$(nvram get wan_proto)" == "pptp" ]; then
    WAN_IF="$(nvram get pptp_ifname)"
else
    WAN_IF="$(nvram get wan_ifname)"
fi

iptables -I FORWARD -o $WAN_IF -m state --state NEW -j REJECT --reject-with icmp-host-prohibited
iptables -I FORWARD -o $WAN_IF -p tcp -m state --state NEW -j REJECT --reject-with tcp-reset

Ref: http://www.dd-wrt.com/phpBB2/viewtopic.php?p=957052