From: Grant Taylor <gtaylor@riverviewtech.net>
To: Mail List - Netfilter <netfilter@vger.kernel.org>
Subject: Re: Theoretical question: need for filter table in the POSTROUTING chain
Date: Thu, 25 Aug 2011 09:51:42 -0500 [thread overview]
Message-ID: <4E56617E.4040704@riverviewtech.net> (raw)
In-Reply-To: <4E5634C3.80908@freemail.hu>
On 08/25/11 06:40, Gáspár Lajos wrote:
> I would like to filter some destination IP-s both on the FORWARD and the
> OUTPUT chains... (For example to stop requests to private IP
> destinations leave our system.)
> I would like to use the REJECT target...
> It would be nince if there would be a filter table in the POSTROUTING
> chain...
>
> What do you think?
How about putting a reject route in the kernel routing table?
That will very easily prevent the packets from leaving your system.
Further, I think the kernel will (by default) send an ICMP packet
indicating that there is no route.
IPTables is great, but sometimes it's better to use a different technology.
Grant. . . .
P.S. Here's a series of commands that I run on my systems.
route add -net 0.0.0.0 netmask 255.0.0.0 reject
route add -net 10.0.0.0 netmask 255.0.0.0 reject
route add -net 169.254.0.0 netmask 255.255.0.0 reject
route add -net 172.16.0.0 netmask 255.240.0.0 reject
route add -net 192.0.2.0 netmask 255.255.255.0 reject
route add -net 192.168.0.0 netmask 255.255.0.0 reject
route add -net 198.51.100.0 netmask 255.255.255.0 reject
route add -net 203.0.113.0 netmask 255.255.255.0 reject
next prev parent reply other threads:[~2011-08-25 14:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-25 11:40 Theoretical question: need for filter table in the POSTROUTING chain Gáspár Lajos
2011-08-25 14:51 ` Grant Taylor [this message]
2011-08-25 15:30 ` Gáspár Lajos
2011-08-26 7:56 ` Jan Engelhardt
2011-08-26 9:13 ` Gáspár Lajos
2011-08-26 9:51 ` Jan Engelhardt
2011-08-26 21:16 ` Christian Benvenuti (benve)
2011-08-26 21:45 ` Jan Engelhardt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4E56617E.4040704@riverviewtech.net \
--to=gtaylor@riverviewtech.net \
--cc=netfilter@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox