netdev - Re: [PATCH v3] iproute2: add support for GRE ignore-df knob

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Date:   Thu, 20 Jul 2017 17:26:28 -0700
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     "Philip Prindeville" <philipp@...fish-solutions.com>
Cc:     netdev@...r.kernel.org, Michele Lucini <mlucini@...earea.com.au>
Subject: Re: [PATCH v3] iproute2: add support for GRE ignore-df knob

On Thu, 20 Jul 2017 13:06:10 -0600
"Philip Prindeville" <philipp@...fish-solutions.com> wrote:

> From: Philip Prindeville <philipp@...fish-solutions.com>
> 
> In the presence of firewalls which improperly block ICMP Unreachable
> (including Fragmentation Required) messages, Path MTU Discovery is
> prevented from working.
> 
> The workaround is to handle IPv4 payloads opaquely, ignoring the DF
> bit.
> 
> Kernel commit 22a59be8b7693eb2d0897a9638f5991f2f8e4ddd ("net: ipv4:
> Add ability to have GRE ignore DF bit in IPv4 payloads") is
> complemented by this user-space changeset which exposes control of
> this setting.
> 
> Reviewed-by: Stephen Hemminger <stephen@...workplumber.org>
> Signed-off-by: Philip Prindeville <philipp@...fish-solutions.com>

Applied, thanks Philip