netdev - Re: [PATCH v3] net/ipv4: always honour route mtu during forwarding

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Message-ID: <CANn89iLO3ktHHX1XK1-Mqva1xoW2OjVs_gFpZoQsGN2yVM3Qag@mail.gmail.com>
Date:   Thu, 24 Sep 2020 11:14:21 +0200
From:   Eric Dumazet <edumazet@...gle.com>
To:     Maciej Żenczykowski <zenczykowski@...il.com>
Cc:     Maciej Żenczykowski <maze@...gle.com>,
        "David S . Miller" <davem@...emloft.net>,
        Linux Network Development Mailing List 
        <netdev@...r.kernel.org>, Willem de Bruijn <willemb@...gle.com>,
        Lorenzo Colitti <lorenzo@...gle.com>,
        Sunmeet Gill <sgill@...cinc.com>,
        Vinay Paradkar <vparadka@....qualcomm.com>,
        Tyler Wear <twear@...cinc.com>,
        David Ahern <dsahern@...nel.org>
Subject: Re: [PATCH v3] net/ipv4: always honour route mtu during forwarding

On Wed, Sep 23, 2020 at 10:18 PM Maciej Żenczykowski
<zenczykowski@...il.com> wrote:
>
> From: Maciej Żenczykowski <maze@...gle.com>
>
> Documentation/networking/ip-sysctl.txt:46 says:
>   ip_forward_use_pmtu - BOOLEAN
>     By default we don't trust protocol path MTUs while forwarding
>     because they could be easily forged and can lead to unwanted
>     fragmentation by the router.
>     You only need to enable this if you have user-space software
>     which tries to discover path mtus by itself and depends on the
>     kernel honoring this information. This is normally not the case.
>     Default: 0 (disabled)
>     Possible values:
>     0 - disabled
>     1 - enabled
>
>
> Signed-off-by: Maciej Żenczykowski <maze@...gle.com>

Reviewed-by: Eric Dumazet <edumazet@...gle.com>