From: ratheesh k <ratheesh.ksz@gmail.com>
To: billprozac@gmail.com
Cc: netfilter@vger.kernel.org, Jan Engelhardt <jengelh@medozas.de>
Subject: Re: NAT table bypass for local traffic
Date: Fri, 30 Apr 2010 12:52:45 +0530 [thread overview]
Message-ID: <s2xcfeab66d1004300022ub22078fby6a32f58f576b5e36@mail.gmail.com> (raw)
In-Reply-To: <001636c5c15232dea504855f65c2@google.com>
On Thu, Apr 29, 2010 at 6:07 PM, <billprozac@gmail.com> wrote:
> The echo-reply does not.
>
> On Apr 29, 2010 2:25am, ratheesh k <ratheesh.ksz@gmail.com> wrote:
>> >>the outgoing echo-reply matches to it and thus does
>>
>> > not show up in nat OUTPUT/POSTROUTING.
>>
>>
>>
>> Does echo reply will show up in nat PREROUTING chain ?
>>
>>
>>
>> Thanks,
>>
>> Ratheesh
>>
>>
Is icmp different from other protocol packets ?
My understanding is : - { In a router } whenever a packet hits
PREROUTING chain , a tuple is created and state is made NEW by
conntrack module . When the packet goes out of POSTROUTING chain,
install original and reply direction tuples in hash table . When
reply packet comes back and hits PREROTUING chain , state is made
ESTABLISHED .
So , in icmp , whenever request goes out itself , state will be made
ESTABLISHED ???
Thanks,
Ratheesh
>>
>> On Thu, Apr 29, 2010 at 2:25 AM, Sven-Haegar Koch haegar@sdinet.de> wrote:
>>
>> > On Wed, 28 Apr 2010, Bill Prochazka wrote:
>>
>> >
>>
>> >> A more simple example is that ICMP echo requests
>>
>> >> go out the nat table's output chain, but ICMP echo replies do not.
>>
>> >
>>
>> > The incoming ICMP echo-request (should be visible in PREROUTING) sets up
>>
>> > a conntrack entry, the outgoing echo-reply matches to it and thus does
>>
>> > not show up in nat OUTPUT/POSTROUTING.
>>
>> >
>>
>> > c'ya
>>
>> > sven-haegar
>>
>> >
>>
>> > --
>>
>> > Three may keep a secret, if two of them are dead.
>>
>> > - Ben F.
>>
>> > --
>>
>> > To unsubscribe from this list: send the line "unsubscribe netfilter" in
>>
>> > the body of a message to majordomo@vger.kernel.org
>>
>> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
>> >
>>
next prev parent reply other threads:[~2010-04-30 7:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-28 17:19 NAT table bypass for local traffic Bill Prochazka
2010-04-28 17:59 ` Steve Fink
2010-04-28 19:46 ` Jan Engelhardt
2010-04-28 20:50 ` Bill Prochazka
2010-04-28 20:55 ` Sven-Haegar Koch
2010-04-29 6:25 ` ratheesh k
[not found] ` <001636c5c15232dea504855f65c2@google.com>
2010-04-30 6:25 ` ratheesh k
2010-04-30 7:22 ` ratheesh k [this message]
2010-05-01 4:23 ` ratheesh k
2010-05-01 14:29 ` Pascal Hambourg
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=s2xcfeab66d1004300022ub22078fby6a32f58f576b5e36@mail.gmail.com \
--to=ratheesh.ksz@gmail.com \
--cc=billprozac@gmail.com \
--cc=jengelh@medozas.de \
--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;
as well as URLs for NNTP newsgroup(s).