nanog mailing list archives
Re: NIST and SP800-119
From: Douglas Otis <dotis () mail-abuse org>
Date: Wed, 16 Feb 2011 15:44:11 +0800
On 2/15/11 11:09 PM, Joe Abley wrote:
Routers indicate local MTUs, but minimum MTUs are not assured to have 1280 octets when IPv4 translation is involved. See Section 5 in rfc2460. (1280 minus 40 for the IPv6 header and 8 for the Fragment header.) Bill suggested this could even be smaller. This also ignores likely limited resources to resolve addresses within a /64. Public facing servers might be placed into much smaller ranges to avoid supporting 16M multicast. Also there might be a need to limit ICMPv6 functions as well, depending upon the features found in layer-2 switches.On 2011-02-14, at 21:41, William Herrin wrote:On Mon, Feb 14, 2011 at 7:24 PM, TR Shaw<tshaw () oitc com> wrote:Just wondering what this community thinks of NIST in general and their SP800-119 ( http://csrc.nist.gov/publications/nistpubs/800-119/sp800-119.pdf ) writeup about IPv6 in particular.Well, according to this document IPv4 path MTU discovery is, "optional, not widely used."Optional seems right. Have there been any recent studies on how widely pMTUd is actually used in v4? More contentious is that Path MTU discovery is "strongly recommended" in IPv6. Surely it's mandatory whenever you're exchanging datagrams larger than 1280 octets? Otherwise the sender can't fragment.
-Doug
Current thread:
- NIST and SP800-119 TR Shaw (Feb 14)
- Re: NIST and SP800-119 William Herrin (Feb 14)
- Re: NIST and SP800-119 Joe Abley (Feb 15)
- Re: NIST and SP800-119 William Herrin (Feb 15)
- Re: NIST and SP800-119 Joe Abley (Feb 15)
- Re: NIST and SP800-119 Steven Bellovin (Feb 15)
- Re: NIST and SP800-119 Mohacsi Janos (Feb 15)
- Re: NIST and SP800-119 Mans Nilsson (Feb 15)
- Re: NIST and SP800-119 Joe Abley (Feb 15)
- Re: NIST and SP800-119 Jared Mauch (Feb 15)
- Re: NIST and SP800-119 William Herrin (Feb 14)
- Re: NIST and SP800-119 Douglas Otis (Feb 15)
- Re: NIST and SP800-119 Joe Abley (Feb 16)
- Re: NIST and SP800-119 Douglas Otis (Feb 16)