====== GRE and GIF Tunnels ======

===== Diagram =====
{{:freebsd:freebsd_tunnels.svg|}}

===== Tunnel Script =====
<file bash gre.sh>
#!/bin/sh

TUNNEL_IF="gre0"
MYSELF_EXT=""
MYSELF_TUNNEL=""

OTHER_EXT=""
OTHER_TUNNEL=""
OTHER_NET=""


if [ "`ifconfig ${TUNNEL_IF} 2>&1 | grep flags`" != "" ]
then
        ifconfig ${TUNNEL_IF} destroy
fi

ifconfig ${TUNNEL_IF} create
ifconfig ${TUNNEL_IF} ${MYSELF_TUNNEL} ${OTHER_TUNNEL} netmask 255.255.255.252
ifconfig ${TUNNEL_IF} tunnel ${MYSELF_EXT} ${OTHER_EXT}
route add ${OTHER_NET} ${OTHER_TUNNEL}
</file>

{{:freebsd:freebsd_tunnels.svg.odg|}}