All of lore.kernel.org
 help / color / mirror / Atom feed
From: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
To: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: Network Development <netdev@vger.kernel.org>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Andrew Lunn <andrew@lunn.ch>
Subject: Re: warnings from MTU setting on switch ports
Date: Mon, 30 Nov 2020 23:50:34 +0100	[thread overview]
Message-ID: <2d4024ef-f80a-475f-a247-e02971b55152@prevas.dk> (raw)
In-Reply-To: <20201130223507.rav22imba73dtfxb@skbuf>

On 30/11/2020 23.35, Vladimir Oltean wrote:
> On Mon, Nov 30, 2020 at 11:13:39PM +0100, Rasmus Villemoes wrote:

>> FWIW, on a 4.19 kernel, I can do 'ping -s X -M do' for X up to 1472
>> for IPv4 and 1452 for IPv6, but I don't think that tells me much about
>> what the hardware could do.
> 
> IP will get fragmented by the stack to the interface's MTU.

Nope, that's what the '-M do' is for:

# ping -M do -s 1880 169.254.246.13
PING 169.254.246.13 (169.254.246.13) 1880(1908) bytes of data.
ping: local error: message too long, mtu=1500

Rasmus

  reply	other threads:[~2020-11-30 22:51 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-30 14:30 warnings from MTU setting on switch ports Rasmus Villemoes
2020-11-30 16:04 ` Vladimir Oltean
2020-11-30 22:13   ` Rasmus Villemoes
2020-11-30 22:35     ` Vladimir Oltean
2020-11-30 22:50       ` Rasmus Villemoes [this message]
2020-11-30 23:11       ` Andrew Lunn
2020-12-05 14:49     ` vlan_filtering=1 breaks all traffic (was: Re: warnings from MTU setting on switch ports) Rasmus Villemoes
2020-12-05 15:45       ` Russell King - ARM Linux admin
2020-12-05 16:02         ` vlan_filtering=1 breaks all traffic Rasmus Villemoes
2020-12-05 19:03       ` vlan_filtering=1 breaks all traffic (was: Re: warnings from MTU setting on switch ports) Vladimir Oltean
2020-12-05 20:13         ` vlan_filtering=1 breaks all traffic Rasmus Villemoes
2020-12-06 19:45           ` Vladimir Oltean
2020-12-07 19:43             ` Rasmus Villemoes
2020-12-07 20:15               ` Vladimir Oltean
2020-12-08  2:22                 ` Andrew Lunn

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=2d4024ef-f80a-475f-a247-e02971b55152@prevas.dk \
    --to=rasmus.villemoes@prevas.dk \
    --cc=andrew@lunn.ch \
    --cc=f.fainelli@gmail.com \
    --cc=netdev@vger.kernel.org \
    --cc=vladimir.oltean@nxp.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.