Debian

/etc/network/interfaces

# IP over DNS
iface tun0 inet static
        address 10.0.0.42
        netmask 255.255.255.0
        mtu 500 # optional, may solve ssh problems
        post-up route add -host `grep nameserver /etc/resolv.conf |head -1|awk '{print $2}'` gw `netstat -rn | grep ^0.0.0.0 | awk '{ print $2 }'` ; route del default ; route add -net default gw 10.0.0.1
        post-down dhclient

/etc/default/nstx

NSTX_DOMAIN="tunnel._your_domain"

NSTX_DNS_SERVER=`grep nameserver /etc/resolv.conf |head -1|awk '{print $2}'`

start_nstxcd=yes

ifup_tun=tun0

Manual/ručno ili distribution neovisno

# DNS_IP_FROM_DHCP - check it in /etc/resolv.conf after successful dhcp
# GW_IP_FROM_DHCP - check it after netstat -rn
# wlan0 - or whatever is your network interface (ie. eth1)

nstxcd tunnel.bljak.org DNS_IP_FROM_DHCP

modprobe tun
ifconfig tun0 up 10.0.0.2 netmask 255.0.0.0

route del default
route add -host DNS_IP_FROM_DHCP gw GW_IP_FROM_DHCP dev wlan0
route add default gw 10.0.0.1 tun0