==== /etc/ppp/ip-up.d/01-iprule.sh ====
<code>
ip rule add from $4 lookup $1
ip route add table $1 default dev $1
</code>

==== /etc/ppp/ip-up.d/02-route.sh ====
<code>
ip route add default via $5 || true
</code>

==== Fix MTU ====
<code>
iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
</code>