Re: iptables leaking blocked ip addresses.

["terry l. ridder" <artisticforge@gmail.com>]

hello;

reply below.

On 6/20/05, Sven-Haegar Koch <haegar@sdinet.de> wrote:
> On Mon, 20 Jun 2005, terry l. ridder wrote:
> 
> >>> one example of the leak is below:
> >>>
> >>> 200.0.0.0/8 is dropped if the destination port is 25 (smtp).
> >>
> >> iptables-save(8) output, please. What you posted here doesn't tell us
> >> much.
> >>
> >
> > while i have reservations concerning posting the output of iptables-save
> > i have placed it on my web server:
> >
> > http://204.238.34.206/iptables-save-20jun2005.txt
> 
> You are filtering in the nat table.
>

yes, i am.

> The nat table gets only the first packet from each connection (the one
> that would match -m state --state NEW).
>

that is incorrect. the nat table is getting all packets.

>
> A retransmit from the blocked IP will not be a new connection,
> so it will pass through your rules.
>

again this is incorrect.

> 
> And on your comment to another mail that you are not using connection
> tracking:
> This is wrong. If you have the nat table, you must have ip_conntrack
> loaded - and if its loaded it tracks your connections, even if you
> dont use -m state at all. There is no iptables nat without connection
> tracking.
>

i may have been looking at the wrong window, i will check on that.

> 
> If you must filter in PREROUTING, do it at least in PREROUTING of the
> filter table.
>

why?

> 
> c'ya
> sven
> 


-- 
terry l. ridder ><>