делаем шлюз интернета


#!/bin/sh -e
PATH=/usr/sbin:/sbin:/bin:/usr/bin
# delete all existing rules.
iptables -F
iptables -t nat -F
iptables -t mangle -F
iptables -X
# Always accept loopback traffic
iptables -A INPUT -i lo -j ACCEPT
# Allow established connections, and those not coming from the outside
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -m state --state NEW -i ! ppp0 -j ACCEPT
iptables -A FORWARD -i ppp0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT
# исправляем mtu
iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
# Allow outgoing connections from the LAN side.
iptables -A FORWARD -i eth1 -o ppp0 -j ACCEPT
# Masquerade.
iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
# Don't forward from the outside to the inside.
iptables -A FORWARD -i ppp0 -o ppp0 -j REJECT
#iptables -A FORWARD -i eth0 -o ppp0 -j REJECT
# Enable routing.
echo 1 > /proc/sys/net/ipv4/ip_forward