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. --Steve Bellovin, http://www.cs.columbia.edu/~smb