Development discussion of WireGuard
 help / color / mirror / Atom feed
From: henning.reich@gmail.com
To: wireguard@lists.zx2c4.com
Subject: Question about MTU and Wireguard and the current changes
Date: Mon, 10 Jan 2022 21:37:35 +0100	[thread overview]
Message-ID: <1e345f21-4564-7df8-1aae-32ba14d42779@qupfer.de> (raw)

Hi,
I run in some connection troubles between two wireguards host (one 
running fedora 35, one arch linux). If I tried to transfer large files 
through SSH (SCP or btrfs send/receive thorugh ssh through wireguard 
tunnel) it stucks after a few byte and nothing transfered anymore.

This happens in the last days, so probably an update on one or both 
machines. I also saw, that there some changes on the MTU thing (If I 
remember correctly, a per peer MTU is configurable)

However. My first try was just set the MTU to a lower number (MTU = 
1200) and yes, scp works again.
Okay, so I did the good old ping test. "ping -M do -s $SIZE -c 1 
172.16.0.2" with $SIZE increasing. And that surprised me. It works until 
an Size of 36932 Bytes. Checked with wireguard and "MTU = 36932" and 
yes, scp still working.

Can somebody explain, why the old default setting of "65456" doesn't 
work anymore but the MTU can set to much higher values as typical ones?

Thanks
Henning


             reply	other threads:[~2022-01-10 20:40 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-10 20:37 henning.reich [this message]
2022-01-10 20:56 ` tlhackque

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1e345f21-4564-7df8-1aae-32ba14d42779@qupfer.de \
    --to=henning.reich@gmail.com \
    --cc=wireguard@lists.zx2c4.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).