Re: [v6ops] RFC 4890 ICMPv6 Filtering Recommendations to BCP?

[Sander Steffann <[e-mail]>]

Hi,

> Something that has always bothered me about RFC4890 is the
> following text of Section A.2:
> 
>   "If a network chooses to generate packets that are no larger than the
>   Guaranteed Minimum MTU (1280 octets) and the site's links to the
>   wider Internet have corresponding MTUs, Packet Too Big messages
>   should not be expected at the firewall and could be dropped if they
>   arrive."
> 
> This seems to preclude PTB messages reporting a size smaller
> than 1280, which are necessary to ensure proper operation of
> IPv6, e.g., per the final paragraph of RFC2460, Section 5.
> 
> My recommendation is that the RFC4890, Section A.2 text be dropped
> when preparing the (bis) version for publication as a BCP.

+1

This advise will cause problems with (atomic) fragment requirement in RFC2460 section 5, so it should not be in a BCP.
Sander