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From: Patrick McHardy <kaber@trash.net>
To: Hua Zhong <hzhong@gmail.com>
Cc: "'Eric Paris'" <eparis@redhat.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	davem@davemloft.net, kuznet@ms2.inr.ac.ru, pekkas@netcore.fi,
	jmorris@namei.org, yoshfuji@linux-ipv6.org
Subject: Re: [RFC PATCH] network: return errors if we know tcp_connect failed
Date: Mon, 15 Nov 2010 11:32:10 +0100	[thread overview]
Message-ID: <4CE10C2A.1050801@trash.net> (raw)
In-Reply-To: <017301cb82bf$54540cf0$fcfc26d0$@com>

On 13.11.2010 00:14, Hua Zhong wrote:
>> On 11.11.2010 22:58, Hua Zhong wrote:
>>>> Yes, I realize this is little different than if the
>>>> SYN was dropped in the first network device, but it is different
>>>> because we know what happened!  We know that connect() call failed
>>>> and that there isn't anything coming back.
>>>
>>> I would argue that -j DROP should behave exactly as the packet is
>> dropped in the network, while -j REJECT should signal the failure to
>> the application as soon as possible (which it doesn't seem to do).
>>
>> It sends an ICMP error or TCP reset. Interpretation is up to TCP.
> 
> Huh? It's the OUTPUT chain we are talking about. There is no ICMP error or
> TCP reset.

Of course there is.

ICMP (default):

iptables -A OUTPUT -p tcp -j REJECT

TCP reset:

iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset

The second one will cause a hard error for the connection.

  reply	other threads:[~2010-11-15 10:32 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-11 21:03 [RFC PATCH] network: return errors if we know tcp_connect failed Eric Paris
2010-11-11 21:14 ` Eric Dumazet
2010-11-11 21:58 ` Hua Zhong
2010-11-12  7:36   ` Patrick McHardy
2010-11-12 23:14     ` Hua Zhong
2010-11-15 10:32       ` Patrick McHardy [this message]
2010-11-15 15:47         ` Eric Paris
2010-11-15 15:57           ` Patrick McHardy
2010-11-15 16:04             ` Patrick McHardy
2010-11-15 16:36             ` Patrick McHardy
2010-11-15 16:46               ` David Miller
2010-11-15 20:00           ` Alexey Kuznetsov
2010-11-12 16:08   ` Eric Paris
2010-11-12 16:15     ` Eric Dumazet
2010-11-12 16:35       ` David Lamparter
2010-11-12 16:53         ` Eric Paris
2010-11-12 16:54         ` Patrick McHardy
2010-11-12 17:57           ` a problem tcp_v4_err() Alexey Kuznetsov
2010-11-12 18:12             ` Eric Dumazet
2010-11-12 18:21               ` Eric Dumazet
2010-11-12 18:27                 ` Eric Dumazet
2010-11-12 18:31                   ` Alexey Kuznetsov
2010-11-12 18:29               ` Alexey Kuznetsov
2010-11-12 18:33                 ` Eric Dumazet
2010-11-12 19:22                   ` David Miller
2010-11-12 21:18                     ` Eric Dumazet
2010-11-12 21:36                       ` David Miller
2010-11-12 21:16           ` [RFC PATCH] network: return errors if we know tcp_connect failed David Lamparter
2010-11-12 21:18             ` David Miller
2010-11-12 17:46 ` Alexey Kuznetsov
2010-11-12 19:28   ` David Miller

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