premostenie WIFI Ethernet

$ more /etc/init.d/gateway 

#! /bin/sh

LOCKFILE='/tmp/.gtw.lock'
LOCKFILECONTENTS='This is gateway lockfile, please do not remove'
# If no rules, do nothing.
[ -f /etc/gateway.rules ] || exit 0

case "$1" in
    start)
    if [ -f "$LOCKFILE" ]; then
        echo 'Gateway already running'
        exit 0
    fi
        echo -n "Turning on packet filtering:"

    #/sbin/modprobe ip_masq_ftp #only if using ipchains
    if [ `/sbin/lsmod | grep iptable_nat | wc -l` -lt 1 ]; then
    /sbin/modprobe iptable_nat #only if using iptables
    fi
    
    if [ `/sbin/lsmod | grep  ipt_MASQUERADE | wc -l` -lt 1 ]; then
    /sbin/modprobe ipt_MASQUERADE #only if using iptables
    fi
        /sbin/iptables-restore < /etc/gateway.rules || exit 1

        echo 1 > /proc/sys/net/ipv4/ip_forward
    # for RedHat users, the above line is not needed if you have
    # FORWARD_IPV4=true in /etc/sysconfig/network file

    echo "1" > /proc/sys/net/ipv4/ip_dynaddr
    # the above option is for Dynamic IP users (DHCP,PPP or BOOTP)
        echo "$LOCKFILECONTENTS" > "$LOCKFILE"  
        echo " OK"
        ;;
    stop)
        if [ ! -f "$LOCKFILE" ]; then
            echo 'Strange... lockfile is missing, but I will try to proceed'
        fi
        echo -n "Turning off packet filtering:"
        echo 0 > /proc/sys/net/ipv4/ip_forward

        /sbin/iptables -F
        /sbin/iptables -X
        /sbin/iptables -P INPUT ACCEPT
        /sbin/iptables -P OUTPUT ACCEPT
        /sbin/iptables -P FORWARD ACCEPT
        if [ -f "$LOCKFILE" ]; then
         /bin/rm "$LOCKFILE"
        fi
        echo " OK"
        ;;
    *)
        echo "Usage: /etc/init.d/gateway {start|stop}"
        exit 1
        ;;
esac

exit 0

$ more /etc/gateway.rules 
# Generated by iptables-save v1.3.6 on Sat Aug 25 16:26:19 2007
*mangle
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
COMMIT
# Completed on Sat Aug 25 16:26:19 2007
# Generated by iptables-save v1.3.6 on Sat Aug 25 16:26:19 2007
*filter
:INPUT DROP [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT 
-A INPUT -i ! ppp0 -m state --state NEW -j ACCEPT 
-A FORWARD -i ppp0 -o eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT 
-A FORWARD -i eth0 -o ppp0 -j ACCEPT 
-A FORWARD -i ppp0 -o ppp0 -j REJECT --reject-with icmp-port-unreachable 
COMMIT
# Completed on Sat Aug 25 16:26:19 2007
# Generated by iptables-save v1.3.6 on Sat Aug 25 16:26:19 2007
*nat
:PREROUTING ACCEPT [8:11734]
:POSTROUTING ACCEPT [2:100]
:OUTPUT ACCEPT [2:100]
-A POSTROUTING -o ppp0 -j MASQUERADE 
COMMIT
# Completed on Sat Aug 25 16:26:19 2007