netdev - Re: PMTUD broken inside network namespace with multipath routing

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Message-ID: <c508eeba-c62d-e4d9-98e2-333c76c90161@gmail.com>
Date:   Mon, 3 Aug 2020 07:32:48 -0600
From:   David Ahern <dsahern@...il.com>
To:     mastertheknife <mastertheknife@...il.com>, netdev@...r.kernel.org
Subject: Re: PMTUD broken inside network namespace with multipath routing

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.