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From: mastertheknife <mastertheknife@gmail.com>
To: David Ahern <dsahern@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: PMTUD broken inside network namespace with multipath routing
Date: Mon, 3 Aug 2020 17:24:50 +0300	[thread overview]
Message-ID: <CANXY5y+gfZuGvv+pjzDOLS8Jp8ZUFpAmNw7k53O6cDuyB1PCnw@mail.gmail.com> (raw)
In-Reply-To: <c508eeba-c62d-e4d9-98e2-333c76c90161@gmail.com>

Hi David,

In this case, both paths are in the same layer2 network, there is no
symmetric multi-path routing.
If original message takes path 1, ICMP response will come from path 1
If original message takes path 2, ICMP response will come from path 2
Also, It works fine outside of LXC.


Thank you,
Kfir

On Mon, Aug 3, 2020 at 4:32 PM David Ahern <dsahern@gmail.com> wrote:
>
> On 8/3/20 5:14 AM, mastertheknife wrote:
> > What seems to be happening, is that when multipath routing is used
> > inside LXC (or any network namespace), the kernel doesn't generate a
> > routing exception to force the lower MTU.
> > I believe this is a bug inside the kernel.
> >
>
> Known problem. Original message can take path 1 and ICMP message can
> path 2. The exception is then created on the wrong path.

  reply	other threads:[~2020-08-03 14:25 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-03 11:14 mastertheknife
2020-08-03 13:32 ` David Ahern
2020-08-03 14:24   ` mastertheknife [this message]
2020-08-03 15:38     ` David Ahern
2020-08-03 18:39       ` mastertheknife
2020-08-10 22:13         ` David Ahern
2020-08-12 12:37           ` mastertheknife
2020-08-12 19:21             ` David Ahern
2020-08-14  7:08               ` mastertheknife
2020-09-01 10:40                 ` mastertheknife
2020-09-01 10:44                   ` mastertheknife
2020-09-02  0:42                   ` David Ahern

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