Arch Linux

Moviuro

Member

Registered: 2012-06-03

Posts: 74

MTU fun and systemd-networkd

Hi all,

I'm currently in a hotel and was hit pretty hard by an MTU issue: too much strain on the wifi and BOOM, everything got dropped. Sad me is sad.
Then, let's try you:

$ size=28
$ while ping -M do -s $size 8.8.8.8 -c1; do ((size+=28)); done

This ends up blocking, you can guess why. So here I get these results: ping breaks/stops at

PING 8.8.8.8 (8.8.8.8) 1456(1484) bytes of data.

However, stupidly, I get a 1500MTU on the interface:

3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000

I'm using systemd-networkd and tried adding a UseMTU=true switch but no dice.

So now: what are my options to make the MTU auto-configure itself? why won't UseMTU=true do any difference? Is it my fault or the hotel's?

Cheers,

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