On Tue, Jun 5, 2018 at 2:22 AM, Michael Richardson <mcr@sandelman.ca> wrote:

Jonas Mårtensson <martensson.jonas@gmail.com> wrote:
> Speaking about systemd defaults, they just enabled ecn for outgoing
> connections:

> https://github.com/systemd/systemd/pull/9143

What about PLPMTU? Do you think they might tweak that too?

net.ipv4.tcp_mtu_probing=2
(despite name, applies to IPv6 too)

Maybe, suggest it on their github. But I would maybe propose instead net.ipv4.tcp_mtu_probing=1.

/Jonas