Re: WIndows Updates Fail Via IPv6 - Update!

[Mark Tinka <mark.tinka () seacom mu>]

On 3/Mar/19 23:04, 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.
>
> If you don’t want to do PMTUD then DO NOT SEND packet bigger than the network
> MTU.  For IPv6 set IPV6_USE_MIN_MTU 1 on the socket.  On a properly written
> IP stack this will result in TCP MSS negotiation to the same value.  Yes, it is
> a requirement of TCP to pay attention to this as it becomes the effective MTU
> of the outgoing interface even if it wasn’t explicitly written into the RFC
> that defined IPV6_USE_MIN_MTU.

You're most welcome to my choir group, good sir.

Mark.