Re: IPv6 path MTU discovery not working (large number of retransmited TCP data packets)

[Andy Ruhl <acruhl%gmail.com@localhost>]

On Mon, May 26, 2025 at 7:07 PM Robert Elz <kre%munnari.oz.au@localhost> wrote:
> The number 1 rule for IPv6 routing is to *always* use a link local
> address for the next hop, for everything.   Never anything else,
> whatever seems more convenient, and whatever looks like it might be
> working (the code is resilient, lots of things will often mostly
> work).

That was long!

You said a lot of stuff that I'm not sure I follow, but I chose this
one to respond to.

Why? Static setup, while not common, is still a thing. A manually
coded gateway that is able to be resolved to a MAC is perfectly fine
to use. Obviously, because the system uses the MAC to route the
traffic to the first hop, not the IP. Once you have the correct MAC,
it matters not which IP was used to get it. Right?

If you have some RFCs to add, that would help. There are so many and I
don't know which ones the cool kids use these days.

Andy