Re: Broken PMTUD for . + TLD servers, was: Re: Smallest Transit MTU

[Iljitsch van Beijnum <iljitsch () muada com>]

On 10-jan-05, at 0:08, Mark Andrews wrote:

>         Well DNS (not EDNS) is limited to 512 octets so you unless there
>         are real links (not ones artificially constrained to demonstrate
>         a issue) this should not be a issue in practice.

No, fortunately not. But it's still VERY wrong and it must be fixed.

>         Note for IPv6 one sets IPV6_USE_MIN_MTU on the UDP socket so this
>         should be a non-issue there.

In IPv6 PMTUD is handled at the IP layer so the second packet that's 
too large will be fragmented at the source, so there is no issue.