if not v6, what?

Wed Sep 8 18:17:58 UTC 2021

> On Sep 7, 2021, at 19:51 , Masataka Ohta <mohta at necom830.hpcl.titech.ac.jp> wrote:
> 
> Niels Bakker wrote:
> 
>>> As for well known port, we can specify non-default port numbers
>>> in URLs (I'm not sure whether it works for mailto: or not) or.
>>> in the future, things like DNS SRV RRs should be helpful.
>> This absolutely doesn't work.
> 
> Thank you very much for your emotional and unfounded
> comment.

It’s neither. There’s no support for SRV RRs in virtually any of the software
that would need it in order for this to be a viable solution and it does not appear
to be coming any time soon.

That’s a fact. Not unfounded and not emotional.

You, yourself admit that mailto: URLs don’t have space for a port number (though
you express uncertainty, I assure you that they don’t).

>> And DNS SRV RRs have roughly zero uptake for stuff that matters (web, email).
> 
> I know SRV and other similar proposals so far are not
> very compatible with URL syntax and should better be
> simplified.

I think the bigger problem is that SRV just hasn’t really caught on and I suspect isn’t
likely to.

In reality, the effort to modify all the code to support SRV wouldn’t be significantly less
than what is required to do IPv6 which would (mostly) obviate the need for SRV as
service-specific IP addresses would be easy to assign. The significant problem here,
no matter how many different ways we attempt to hack around it is address shortage.
The solution to that is more addresses (i.e. IPv6).

>>> Then, to run servers at home, we only need some not-well-known
>>> ports forwarded, which can be default or value added service of
>>> your local ISP, just like fixed IP addresses today.
> 
>> Oh and we need to work around the whole IP reputation system that governs email today.
> IP reputation system must evolve to be IP+port reputation
> system, which is not my problem.

ROFLMAO — as if that’s at all likely to happen.

Further, you have the problem that the port side where this matters is ephemeral
meaning that multiple systems (which need different reputations) share the same
source address+port combination, so it doesn’t really help.

No, IP reputation system must evolve to support 128 bit addresses and some level
of heuristic determination of how many of those 128 bits should be applied to a given
reputation (probably defaulting to 64 and working left from there).

Owen