From: Brian Haley <brian.haley@hp.com>
To: Jarek Poplawski <jarkao2@gmail.com>
Cc: Rob.Townley@gmail.com, netdev@vger.kernel.org,
Omaha Linux User Group <olug@olug.org>,
CentOS mailing list <centos@centos.org>
Subject: Re: Ping Is Broken
Date: Mon, 12 Oct 2009 19:30:26 -0400 [thread overview]
Message-ID: <4AD3BC12.6020409@hp.com> (raw)
In-Reply-To: <4AD3A388.7020709@gmail.com>
Jarek Poplawski wrote:
> Brian Haley wrote, On 10/12/2009 10:36 PM:
>
>> In this case ping is doing an SO_BINDTODEVICE to eth0, so the kernel is going
>> to force the packets out of it, even if it isn't the "correct" interface. If
>> you ran tcpdump you'd probably see an ARP resolution failure, or an ICMP from
>> a gateway.
>
> BTW, SO_BINDTODEVICE is used only to acquire a source address, not the real
> connection (unless I miss something).
No, SO_BINDTODEVICE affects routing, as well as incoming packets - it's in macros
like INET_MATCH(), from what I've seen it restricts a socket to only use the device
specified, irregardless of the source address you're using. For example, you can
bind to 127.0.0.1 and send packets out eth0 if sk_bound_dev_if is set to it if I
remember correctly.
-Brian
next prev parent reply other threads:[~2009-10-12 23:31 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-09 10:16 Ping Is Broken Rob Townley
[not found] ` <7e84ed60910090316ne9224fat81d9c79c58fc713b-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-10-09 16:34 ` Rob Townley
[not found] ` <7e84ed60910090934y2a0d422cr158aa8d15e452f97-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-10-09 16:44 ` Rob Townley
2009-10-12 9:47 ` Jarek Poplawski
2009-10-12 19:14 ` Rob Townley
2009-10-12 20:43 ` Jarek Poplawski
2009-10-12 20:36 ` Brian Haley
2009-10-12 21:28 ` Jarek Poplawski
2009-10-12 21:45 ` Jarek Poplawski
2009-10-12 23:30 ` Brian Haley [this message]
2009-10-13 5:10 ` Jarek Poplawski
2009-10-13 13:48 ` Brian Haley
[not found] ` <006a01ca4a10$a1a4ba60$e4ee2f20$@com>
[not found] ` <7e84ed60910111032s2f03b6dew5c756895872e1a0c@mail.gmail.com>
[not found] ` <000301ca4b13$60a26e00$21e74a00$@com>
[not found] ` <7e84ed60910121115i30ec3512uce46cf0ff3b3954c@mail.gmail.com>
[not found] ` <Pine.LNX.4.64.0910121934360.26068@pakmon.pakint.net>
2009-11-22 20:10 ` [olug] " Rob Townley
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