Re: Linux Firewalls

[David Correa <tech () linux-tech com>]

Charles,

On Thu, 20 Dec 2001, McKee, Charles wrote:
> I have a quick question about an article I have just read in the latest
> addition of Sys Admin.

I have not seen the article

> In the article it states that one can keep alive IPChains and Natd when
> you do a shutdown -h on a Linux box, that is running Red hat 6.2.

If the rules are on a shell script and is called at boot time
(via rc.local or similar) the rules will become enabled
after reboot. If you only entered the rules via the
command line they will not show up (as far as I can remember)
ipchains -L will be default.

> I was wondering will this work on for the latest versions of Linux and
> what about the BSD family, Mandrake or even Solaris.

BSD's uses ipf and pf (OpenBSD 3.0).

> Also if this is true, can your firewall be exploited or even the NatD
> daemon.

If you do a shutdown -h the box goes off, no ip forwarding possible,
and the box will be as secured as the location is.

In any case, you should be using iptables (netfilter) on
kernel 2.4.x (2.4.16 recommended) so you can have a stateful
firewall, and also take advantage of other netfilter and the
Linux advanced routing options.

Regards,

::dc::

David Correa RHCE CCNA    _    _ _  _ _  _ _  _    ___ ____ ____ _  _
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