From mboxrd@z Thu Jan  1 00:00:00 1970
From: Changli Gao <xiaosuo@gmail.com>
Subject: Re: RFC: netfilter: synproxy iptables target
Date: Thu, 20 May 2010 22:42:25 +0800
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Cc: Patrick McHardy <kaber@trash.net>,
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To: Eric Dumazet <eric.dumazet@gmail.com>
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On Thu, May 20, 2010 at 10:32 PM, Eric Dumazet <eric.dumazet@gmail.com>=
 wrote:
> Le jeudi 20 mai 2010 =C3=A0 22:21 +0800, Changli Gao a =C3=A9crit :
>
>>
>> pure synproxy can be used on firewall to protect the internal server=
s,
>> which don't support neither syncookies and synproxy, from the attack
>> of SYN-flood.
>>
>
> protecting servers using conntracking ?
>
> Thats seems very dangerous to me.

If NAT is needed, conntracking is needed in any way. The conntrack
won't be confirmed until the connection between firewall and client is
established.

>
>> synproxy with defered connection relay acts as a layer 7 proxy, but
>> works in kernel space totally, unlike tcp splice tech., which needs
>> the applications in user space parse the requests, and establish the
>> connections.
>>
>
> In the example given, only non persistent connections are handled...
>
> These days, browsers and servers dont establish one socket per http
> request...
>
>

Yea. But some users still use non persistent connections, as they want
to fetch URLs in parallel.

--=20
Regards=EF=BC=8C
Changli Gao(xiaosuo@gmail.com)
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