From: Ulrich Weber <ulrich.weber@googlemail.com>
To: Jan Engelhardt <jengelh@medozas.de>
Cc: Leo Baltus <Leo.Baltus@omroep.nl>, netfilter-devel@vger.kernel.org
Subject: Re: ip6tables breaks dnssec?
Date: Wed, 27 Apr 2011 12:43:19 +0200 [thread overview]
Message-ID: <4DB7F347.1080107@gmail.com> (raw)
In-Reply-To: <alpine.LNX.2.01.1104271200480.12004@obet.zrqbmnf.qr>
Each fragmented IPv6 packets will traverse netfilter separately,
in contrast to IPv4, where its only one refragmented packet.
"ip6tables -A INPUT -j ACCEPT -p udp --dport 53" will only match the
first fragment, where the UDP header can be found. To match the
additional fragments, you have to insert these rules:
ip6tables -I INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
ip6tables -I OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
Cheers
Ulrich
On 04/27/2011 12:08 PM, Jan Engelhardt wrote:
> On Wednesday 2011-04-27 10:57, Leo Baltus wrote:
>
>> Hi,
>>
>> When doing recusive dns queries to dnssec-enbled servers it looks like
>> ip6tables does not assemble udp packets before filtering takes place.
>> This results in fragments being dropped.
>
> You need to have nf_defrag_ipv6 loaded for automatic defragmentation.
> There are only a few components that depend on it - nf_conntrack and
> TPROXY, so it may not be autoloaded if you do not use either.
> --
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next prev parent reply other threads:[~2011-04-27 10:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-27 8:57 ip6tables breaks dnssec? Leo Baltus
2011-04-27 10:08 ` Jan Engelhardt
2011-04-27 10:43 ` Ulrich Weber [this message]
2011-04-27 10:56 ` Leo Baltus
2011-04-27 11:22 ` Jan Engelhardt
2011-04-27 11:41 ` Leo Baltus
2011-05-06 14:05 ` Leo Baltus
2011-04-27 11:43 ` Ulrich Weber
2011-04-27 12:54 ` Stephen Clark
2011-04-27 13:01 ` Jan Engelhardt
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