Re: [nznog] Cloudflare IPv6 MTU

On 04/02/2015 10:55, Jasper Bryant-Greene wrote:

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On 4/02/2015, at 10:33 am, Jeremy Visser wrote:

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On 3/02/2015 18:46, Mark Foster wrote: I realise there is this ideal world where we don't have to transit networks beyond our control, but why is (1) not condoned in your view?

Because history has shown that the "be liberal in what you accept, conservative in what you emit" mantra is actually really bad at motivating others to fix their broken stuff.

OTOH, it's pretty good at keeping networks working.

And, if we're getting philosophical, it's morally neutral: it doesn't matter whether the broken stuff is intentional or human error, and it doesn't needlessly punish an innocent user. But there is one case where the mantra is dangerous: it tells you not to implement BCP 38. In terms of IPv6 MTU size, a server site that limits its outbound MTU to 1280, but accepts larger inbound packets, is just playing safe. Brian