nanog mailing list archives
Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms
From: William Herrin <bill () herrin us>
Date: Fri, 8 Mar 2019 09:40:42 -0800
On Fri, Mar 8, 2019 at 5:45 AM Brandon Martin <lists.nanog () monmotha net> wrote:
ICMP is nice in that it's totally protocol agnostic and doesn't require altering of packets in transit. It's a shame we can't reasonably rely on it being delivered.
Path MTU discovery is broken. It's the one place in TCP/IP where the end-to-end principle was thrown out the window and we keep on paying for it. A correct solution would have been for the intermediate router to truncate the packet. Not fragment, truncate. On receiving the truncated packet, the RECIPIENT (not the intermediate router) would report the truncation to the sender. This could easily have been done at layer 3, just like existing PMTUD. IPv4's inventors did a brilliant job with what they knew at the time. IPv6's inventors not so much. Sadly, they were too busy figuring out how to make IPv6 integrate well with ATM. Seriously, if you dig up a copy of the original IPng book I think it's chapter 3. Regards, Bill Herrin -- William Herrin ................ herrin () dirtside com bill () herrin us Dirtside Systems ......... Web: <http://www.dirtside.com/>
Current thread:
- RE: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms, (continued)
- RE: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms adamv0025 (Mar 12)
- Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms Saku Ytti (Mar 12)
- RE: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms adamv0025 (Mar 13)
- Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms Masataka Ohta (Mar 09)
- Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms Jean-Daniel Pauget (Mar 08)
- Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms Saku Ytti (Mar 08)
- Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms Brandon Martin (Mar 08)
- Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms Jeroen Massar (Mar 08)
- Re: ICMPv6 "too-big" packets ignored (filtered ?) by Cloudflare farms William Herrin (Mar 08)