<div dir="ltr"><div>It's been reverted.</div><div><br></div><div>commit 95ab9eff1e24cf996cd4111a93e3a8b29ff0f524</div><div>Author: Andrew Jeddeloh <<a href="mailto:andrewjeddeloh@gmail.com">andrewjeddeloh@gmail.com</a>></div><div>Date:   Thu Oct 5 03:58:02 2017 -0700</div><div><br></div><div>    Revert "networkd: change UseMTU default to true. (#6837)" (#6950)</div><div>    </div><div>    This reverts commit 22043e4317ecd2bc7834b48a6d364de76bb26d91.</div><div>    UseMTU is broken on real hardware and should not be enabled by default.</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Sep 30, 2017 at 5:30 AM, Andrew Jeddeloh <span dir="ltr"><<a href="mailto:andrew.jeddeloh@coreos.com" target="_blank">andrew.jeddeloh@coreos.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I saw in <a href="https://github.com/systemd/systemd/pull/6936" rel="noreferrer" target="_blank">https://github.com/systemd/<wbr>systemd/pull/6936</a> that networkd's<br>
UseMTU will be enabled by default in 235. There is an bug<br>
<a href="https://github.com/systemd/systemd/issues/6593" rel="noreferrer" target="_blank">https://github.com/systemd/<wbr>systemd/issues/6593</a> that causes networkd to<br>
loop continually setting and unsetting the MTU on most real hardware<br>
if UseMTU is set and the the DHCP lease specifies a larger value than<br>
what the driver is currently using.<br>
<br>
This can be reproduced on with the e1000 ethernet driver as well as<br>
ixgbe. See <a href="https://github.com/coreos/bugs/issues/1827#issuecomment-321129028" rel="noreferrer" target="_blank">https://github.com/coreos/<wbr>bugs/issues/1827#issuecomment-<wbr>321129028</a><br>
for reproduction setups using a Container Linux image and dnsmasq<br>
locally.<br>
<br>
This bug should be fixed before UseMTU is enabled by default.<br>
<span class="HOEnZb"><font color="#888888"><br>
-Andrew Jeddeloh<br>
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