IP Forwading from Local IP to Live IP

Jason Opperisano opie at 817west.com
Tue Apr 19 13:42:26 CEST 2005

On Tue, Apr 19, 2005 at 03:55:18PM +0800, elg3ne wrote:
> Hi guys, Im new to iptables.. hope someone can help me to this.
> The situation is this, I have a webserver running on a local network machine
> ( & I want it to be accessible outside my network. Is it
> possible?
> setup is like this:
> workstation ( ---> HUB ---> server ( LIVE IP, accessible
> everywhere on the net )
> when user access the live IP ex. can he forward to get the files on
> the worstation?

three line guide to "port-forwarding:"

  iptables -t nat -A PREROUTING -i $EXT_IF -p tcp --dport $OUTSIDE_PORT \
    -j DNAT --to-destination $INSIDE_HOST_IP:$INSIDE_PORT

  iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT

  iptables -A FORWARD -i $EXT_IF -p tcp --syn \

where example values for all the variables are:




"Peter: Lois, When I'm through with them, our kids will be so smart,
 they'll be able to program their own VCRs without spilling piping hot
 gravy all over myself."
        --Family Guy

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