[ale] I'm an iptables idiot

[Michael D. Hirsch]

On Thursday 11 March 2004 12:33 pm, Frank S. Glass wrote:
> Make sure that you also have a filter table rule for the port.  After the
> PREROUTING nat chain a packet still must pass through the filter table.

Can you be a little more explicit?  I'm such an iptables idiot I don't know 
what that means.

Here's what I have that I'm told should work:

[root at radium root]# /etc/init.d/iptables status
Table: filter
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
Table: nat
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination
DNAT       tcp  --  anywhere             anywhere           tcp dpt:2402 
to:10.0.26.52:2401

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination
MASQUERADE  all  --  anywhere             anywhere

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
[root at radium root]#

Thanks,

Michael

> Frank
>
> Quoting "Michael D. Hirsch" <mhirsch at nubridges.com>:
> > What am I doing wrong?  I'm trying to forward port 2402 on one system to
> > port 2401 on another.  This should be easy.
> >
> > According to google, the solutions is the obviosu one, something like:
> > iptables -A PREROUTING -t nat -p tcp  --dport 2402 -j DNAT --to  \
> >            10.0.25.52:2401
> >
> > In my searching I came across a bunch of folks who tried the obvious
> > solution, it didn't work, so they asked the same question I'm asking.
> > The responses were all variations on "You should try the obvious
> > solution."
> >
> > I believe forwarding is turned on:
> > # cat /proc/sys/net/ipv4/ip_forward
> > 1
> >
> > Suggestions?  I've gotta believe I'm missing something stupid.
> >
> > Thanks,
> >
> > Michael
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