ip routing wount work (this set-up worked fine on Debian thou)

Lechium · 08-01-2004, 11:39 PM

Hi.
I have my windowsbox hooked up to linuxbox's eth1, and am trouting to turn linuxbox into a router. Now it worked fine before when i had debian. Right now my two computers can ping each other, however I cannot set up ip forwarding properly. The command /usr/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE seems to have no effect, as windowsbox is still offline. How are you supposed to set up ip routing in slack, after all?

note -- set up is:
internet -- eth0 -- linux -- eth1 -- windows netcard -- windows

thank you

gbonvehi · 08-01-2004, 11:48 PM

Try before that: echo "1" > /proc/sys/net/ipv4/ip_forward

Lechium · 08-01-2004, 11:51 PM

that worked. thanks!

btw I understand that it runs ip forwaring program, but why echo "1" < in front?

gbonvehi · 08-01-2004, 11:56 PM

It outputs a 1 character to that file, 1 means ON

/proc/sys/net/ipv4/ip_forward is not a program, it's a configuration of that process (take a look at the files under /proc and you'll understand what i mean).

Lechium · 08-02-2004, 12:25 AM

cool thanks

SiegeX · 08-02-2004, 01:16 AM

Just incase you didnt know, that echo "1" command wont survive a reboot, so you will have to place that in some startup script. Or you can take my recommendation and get IPKungfu which is nothing more than a very robust and easy-to-configure iptables firewall that sets all these things for you. You can get IPKungfu at => www.linuxkungfu.org

If you decide to use it, here is the slackware startup script that I made for it.

Code:

#!/bin/sh
#
# ipkungfu startup script
#
# description: Starts the ipkungfu firewall
#
# by Rocco Stanzione, based on the iptables script:
# IPKungFu Author:      Rocco Stanzione <grasshopper@linuxkungfu.org>
# Init Script Author:   Sean Donner <siegex@identityflux.com>

IPKF_CONFIG=/etc/ipkungfu/ipkungfu.conf
IPKF_EXE=/usr/local/sbin/ipkungfu

if ! [ -x $IPKF_EXE ] ; then
        echo $IPKF_EXE is not executable!
        exit
fi

if ! [ -r $IPKF_CONFIG ] ; then
        echo $IPKF_CONFIG cannot be read
        exit
fi

KERNELMAJ=`uname -r | awk -F . '{print $1}'`
KERNELMIN=`uname -r | awk -F . '{print $2}'`

if [ "$KERNELMAJ" -lt 2 ] ; then
        echo Kernel Major Number is less than 2
        exit

elif [ "$KERNELMAJ" -ge 2 -a "$KERNELMIN" -lt 3 ] ; then
        echo Kernel Minor Number is less than 3
        exit
fi

lsmod 2>&1 /dev/null | grep -qi ipchains && echo "ipchains module loaded.  Aborting.  Try rmmod ipchains and try again."

start() {
        echo -n "Starting ipkungfu: "
        $IPKF_EXE --init && echo -e "\t\t\t\t\t\t[  OK  ]" || echo -e "\t\t\t\t\t\t[  FAILED  ]"
}

stop() {
        $IPKF_EXE --disable
}

case "$1" in
  start)
        start
        ;;

  stop)
        stop
        ;;

  restart|reload)
        # "restart" is really just "start" as this isn't a daemon,
        #  and "start" clears any pre-defined rules anyway.
        #  This is really only here to make those who expect it happy
        start
        ;;

  status)
        $IPKF_EXE --check
        ;;

  panic)
        $IPKF_EXE --panic
        ;;
  *)
        echo "Usage: $0 {start|stop|restart|status|panic}"
        exit
esac

Lechium · 08-02-2004, 11:46 AM

thanks!