Subject: Re: IPv6 Comment
To: Greywolf <>
From: Matthew Orgass <>
List: current-users
Date: 09/08/2000 14:16:25
On Fri, 8 Sep 2000, Greywolf wrote:

> On Thu, 7 Sep 2000, Sean Doran wrote:
> # What sucks is the fact that you cannot distinguish what from where
> # in either IPv4 or IPv6.
> Did I miss something?  (Bill, gimme another 'what' point...).
> How do you mean this?  Sure you can.  Don't IP headers carry
> host-from/port-from host-to/port-to
> information somewhere in the first chunk of space?

  No, IP does not have ports.  This is in TCP and UDP and is why port
translators are necessarily transport protocol dependent.

> Isn't host-from a where, and port-from a what?

  Not really.  Ports are sub-host identifiers.

> # But see
> # which is a better solution than either NAT etc. or IPv6.
> Hm.  Have to do that when awake.

  Unfortunately, they don't provide any real information about what they
are proposing.

> You cannot simply compress net addresses without losing something
> somewhere.  If you don't have the IP addresses sufficient to negotiate
> the namespace/address space, something's got to give.  Since the port
> and the protocol are the only other things in the header (outside of
> the MAC address and the length, either of which will screw you if
> they don't match right), they're the only parameters which can be
> dinked with in order to provide a wide enough space of addressing,
> and I somehow don't think you want to be mucking with the protocol number
> as a means of address expansion :-).

  Um, IP headers don't have MAC addresses either.

  All you need to do to separate what from where is have two numbers in
each header, one used for routing and the other for host identification.

Matthew Orgass