Re: [Ntp] Is the real MTU still 576?
Erik Kline <ek.ietf@gmail.com> Sun, 21 June 2020 01:58 UTC
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From: Erik Kline <ek.ietf@gmail.com>
Date: Sat, 20 Jun 2020 18:58:33 -0700
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To: Hal Murray <hmurray@megapathdsl.net>
Cc: NTP WG <ntp@ietf.org>
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Subject: Re: [Ntp] Is the real MTU still 576?
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On Sun, Jun 14, 2020 at 5:52 PM Hal Murray <hmurray@megapathdsl.net> wrote: > > > There was mention in the Roughtime discussion that the official minimum MTU is > still 576. Leaving aside the question of what size is practical in the face of anti-DDoS measures, and to expand a bit on Marcus's comment on that thread, the 576 number is the minimum size that an IPv4 node is required to be able to reassemble. The actual MTU of any link may be much smaller but hosts must be able to reassemble up to a 576 byte packet from however many fragments. See also RFC 791 section 3.1 and RFC 1122 sections 3.3.2 and 3.3.3. This is a subtly different thing from the IPv6 min MTU of 1280. (See references to 1500 in RFC 8200 section 5.)
- [Ntp] Is the real MTU still 576? Hal Murray
- Re: [Ntp] Is the real MTU still 576? Steven Sommars
- Re: [Ntp] Is the real MTU still 576? Daniel Franke
- Re: [Ntp] Is the real MTU still 576? Watson Ladd
- Re: [Ntp] Is the real MTU still 576? Erik Kline