sudo iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE
sudo iptables -A FORWARD -i tun0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i wlan0 -o tun0 -j ACCEPT

# Generated by resolvconf
search a.my-company.com b.my-company.com c.my-company.com
nameserver 10.0.0.1           # VPN DNS server
nameserver 10.4.0.1           # VPN DNS server
nameserver 194.168.4.100      # ISP DNS server
nameserver 194.168.8.100      # ISP DNS server

IP 10.4.119.198.35387 > [VPN DNS SERVER 1].domain: 12662+ A? some.website.com. (38)
IP [VPN DNS SERVER 1].domain > 10.4.119.198.35387: 12662 1/13/13 A [Resolved IP] (486)
IP 10.4.119.198 > [VPN DNS SERVER 1]: ICMP 10.4.119.198 udp port 35387 unreachable, length 522