Re: NIST and SP800-119

[Mohacsi Janos <mohacsi () niif hu>]

On Tue, 15 Feb 2011, Steven Bellovin wrote:

> On Feb 15, 2011, at 10:36 54AM, William Herrin wrote:
>
> > On Tue, Feb 15, 2011 at 10:09 AM, Joe Abley <jabley () hopcount ca> wrote:
> > > 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?
> >
> > Hi Joe,
> >
> > Are you aware of a TCP implementation in an OS that shipped within the
> > last decade but doesn't enable IPv4 pMTUd by default? Each version of
> > Windows and all the major unixes use it on every TCP connection unless
> > you explicitly turn it off.
> All modern TCPs support it; many firewalls are configured to block the necessary ICMPs.

Then probably blackholing themselves the firewall operators....
Best Regards,
                Janos Mohacsi