Linux Netfilter discussions
 help / color / mirror / Atom feed
From: Born Without <blackhole@airpost.net>
To: "Steve (Telsat Broadband)" <steve@telsatbb.vu>
Cc: netfilter@vger.kernel.org
Subject: Re: FW: Packets missing the NAT table
Date: Sun, 06 Jan 2013 18:08:23 +0100	[thread overview]
Message-ID: <50E9AF87.7070403@airpost.net> (raw)
In-Reply-To: <00a901cdec28$006d1c10$01475430$@telsatbb.vu>

On 06.01.2013 17:08, Steve (Telsat Broadband) wrote:
> Hi All,
>
> I’m just trying to debug an issue on our network and I’ve noticed that some
> packets are being missed from some rules in the NAT table.
>
> Do all packets go through the NAT table or is there some exclusion?  I’m
> seeing the packet hitting the mangle table as well as the filter table, but
> not the NAT?

What I've read in the past, the nat table is only consulted at 
connection initiation for conntrack state NEW packets.
If conntrack qualifies a packet as INVALID this won't get natted and 
sent out as is (if not dropped from another rule).
Try to catch the invalid packets with:
-m conntrack --ctstate INVALID
and see if these are the suspected ones.


      parent reply	other threads:[~2013-01-06 17:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-06 16:08 FW: Packets missing the NAT table Steve (Telsat Broadband)
2013-01-06 16:54 ` Jan Engelhardt
2013-01-06 16:58   ` Steve (Telsat Broadband)
2013-01-06 17:08 ` Born Without [this message]

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=50E9AF87.7070403@airpost.net \
    --to=blackhole@airpost.net \
    --cc=netfilter@vger.kernel.org \
    --cc=steve@telsatbb.vu \
    /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