nanog mailing list archives

Re: WIndows Updates Fail Via IPv6 - Update!


From: Mark Andrews <marka () isc org>
Date: Wed, 6 Mar 2019 15:09:29 +1100



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


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