On 6 Mar 2019, at 1:30 pm, Fernando Gont <fgont@si6networks.com> wrote:
On 3/3/19 18:04, Mark Andrews wrote:
There are lots of IDIOTS out there that BLOCK ALL ICMP. That blocks PTB getting back to the TCP servers. There are also IDIOTS that deploy load balancers that DO NOT LOOK INSIDE ICMP messages for redirecting ICMP messages to the correct back end. There are also IDOITS that rate limit PTB generation to ridiculously low rates. One should be able to generate PTB at line rate.
Everyone that has configured mss-fix-up has contributed to misunderstanding that you can block ICMP. It is time we had a flag day to REMOVE mss-fix-up from all the boxes you control. We need to get PTB working and unfortunately that means that we need to stop pandering to admins who don’t know how IP is supposed to work. ICMP is NOT optional.
It would seem IETF's intention is to actually move away from ICMPv6-based PMTUD, to the extent that is possible. (RFC4821).
Which is not a reason to not fix broken equipment and misconfigured firewalls. The workarounds are basically there because people deploy broken equipment. Additionally everything isn’t TCP.
Thanks, -- Fernando Gont SI6 Networks e-mail: fgont@si6networks.com PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
-- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org